I have a 2003 VW Passat W8 wagon. I was driving, I zoomed...

I have a 2003 VW Passat W8 wagon. I was driving, I zoomed up to 60 quite nicely after just finishing a repair to my VVT actuators. It idled great again, so I was happy. Just as I thanked my stars etc, the engine cut to idle with m...

I have a 2003 VW Passat W8 wagon. I was driving, I zoomed up to 60 quite nicely after just finishing a repair to my VVT actuators. It idled great again, so I was happy. Just as I thanked my stars etc, the engine cut to idle with my foot on the gas. I limped along with intermittent engine throttle. I decided to try turning the engine off and restating it. It worked and I drive, carefully, around to several errands that day. It got worse and was a real puzzle. I replaced the throttle body. No difference at all. My OBDII showed that the VVT Actuator failure codes WERE GONE, YAY. But it showed a 2101 throttle body actuator motor malfunction and of course with the engine cutting out like that, it recorded timing advanced on the exhaust actuators on both sides of the V8. Errors, not actuator failures. I think it looks like I have an intermittant connection to my Throttle body. How can I, by myself, fix this? If I take it anywhere, the MO if shoos is to find faulty part, replace part with OEM part and done. That's not going to work on a 17 year old car. I drove it all day yesterday and the throttle cut but I pulled my foot of the gas so fast it did not even turn on the engine light. When I was almost home, I floored it and made it fail with the 2101 Throttle body Actuator motor failure. But it's brand new. It's a wiring problem. What can I do?I have had the seat module fail. I just pulled the plugs and out them back on, with some anticorrosion spray and it's worked for 10 more years. I COULD be a corroded connection.

I have had the seat module fail. I just pulled the plugs and out them back on, with some anticorrosion spray and it's worked for 10 more years. I COULD be a corroded connection.oops, I already said thatI'm thinking the most likely place for the connection failure would be its connection to the ECU. But I was just wondering if y'all have seen this and know another way this could have happened.KNOW HOW TO FIX IT. That IS what I need after all.It did sit for most of the summer. It's too hot in Texas at my age. But maybe sitting....but I drove it with the VVT actuators disconnected on one side and it ran fine then. It just idled roughI'm really puzzled. It IS a faulty connection, but which wire? If I studied the schematics, I might find which wires it must be and run new wires in parallel with the existing harness to bypass the bad spot if it measures intermittently on my multimeter, but that's the problem with intermittent failures.Is there a pinout diagnosis procedure for the throttle plug?That would sure help narrow it down. I should add one more important thing. I had a rat make a cozy nest out of my hood liner and it snacked on wires. But I fixed all the wires found by a dealer garage. But is it possible that there's a throttle wire that passes to the underside of the engine, before coming back up to the ECU?I'm very tired. If you put your name and a way to follow up with you in your response, I will read it in email. So feel free to send schematics or pinout diagnostic procedures and anything and if I can get you with a follow-up question or several, that'd be awesome. Thank you so much. This car means so much to me. I've never owned such a fine car in my life. I have a thousand bucks in restoration materials clogging up my house and I've really gone all out this year with new paint, new seals and so much. Carpet shampoo s and seat upholstery. We can't let it die because of a wire. Thanks so very much. Now I'm dead tired and starving. Later.

I forgot to make it clear that no matter what happens, the engine has NEVER EVER died. It only cuts to idle. Also, while the padel is completely unresponsive, I hear some small electric motor whine with a RPM that rises with the throttle position. It's not the throttle Actuator motor like I assumed. It might be the vacuum motor. It's small. It's just a weird factoid. The throttle does do some things, right? But the throttle position just cuts out. Also, I've noticed that it seems like it's getting less debilitating the more I drive it, but that could mean nothing at all. For example, since I'm aware it happens, I'm getting better at lifting my foot quite quickly after I sense the engine cutting to idle. I just wanted to make sure you know this in case it clears a misunderstanding. It idles perfectly now that I fixed the VVT actuator wires. 2 different shops told me this was impossible to fix. They've never heard of silver epoxy. It conducts electricity better than the copper wires that cary the signal the rest of the way. I sometimes suspect that at least one wire has a bad splice. See, I hooked them up backwards first. OMG. After all that work, I had to cut those 4 wires and swap sides. Those easy splice deals as seen on TV, they don't seem to have rosin in them. A bit late but anyway, if there was an intermittant VVT Actuator the engine light would come on. With this problem, as long as I lift my foot instantly when the throttle cuts, I can drive it around all day and never cause the 2101 throttle body actuator motor failure code. So we're back to which wires are controlling the throttle Actuator motor? Those aren't making a good connection somewhere. I'd say the connection to the ECU, but I'd need to know which wires in the plug, and which terminals on the ECU, or wherever those go. It might be the throttle pedal, but I've pumped it a bunch of times and it changed nothing at all, or so it seemed. The connection there could still be failing. Oh, I think I just realized something I hadn't thought of before. And I did shampoo the carpets last spring. Why'd it work so well all summer, even without VVT actuators? Ok, that points away from the throttle pedal completely. There's no sunroof leak either, in case.....(It happens, I HATE sunrooves). Well, in any case, I wanted you to know that the engine never dies, it only cuts to a nice throttle but sometimes it idles high until I restart the engine. It compensates or something. I'm not sure why restarting the engine can clear some problem that was caused by the sudden drop in throttle while the throttle pedal is down. And as I say, I'm learning to carefully feel for throttle cuts and take my foot off so fast that it doesn't cause an engine light, fault, or failure. It's just a pain in the butt. Oh, it also is far more likely to cut out when the throttle is pushed down pretty far. It's much less likely if I drive like an old lady, and it's also easier to lift my foot and prevent a haywire situation. THIS IS the symptom that doesn't fit the bad wire theory. Why is it more likely to cut out the harder I'm pressing the accelerator? I guess that might be an illusion too. It's WAY more dramatic when you're pushing it and it cuts out. OK, this wasn't much help. But it idles like a dream that's about ready for a change of plugs maybe but it's really smooth. Just trying to help. Thank you again. I'm super exhausted now so I'm sorry if I'm not helping. I'm just trying to provide that clue that makes it all click.
Automotive Expert
Hello my name is \*\*\*\*\* \*\*\*\*\* ase master mechanic and I am here to help you with this issue after reading what you have wrote it does sounds as if you have a wiring issue meaning I think it’s a pin fit issue on the connector or a resistance in the signal wire I am going to look up a wire diagram for you and see if we can down to the bottom of this issue ok
Automotive Expert
Here is a diagram
Automotive Expert
what you can do is check for a solid ground and good power also the 5 volt reference and last test the signal wires with a volt meter and you should see the voltage change as you open and close the throttle plate

I'm not sure I understand. Test the signal wires as I literally push open the throttle plate with my hands, pushing the valve open and closed? The 5 volt reference is something that the ECU provides? Or must I provide this? I only need test the voltages on these wires while the throttle is plugged in? This requires using needle leads to pierce the wires? That makes me uneasy. Do you have the pinout diagram of the plug itself? Otherwise, I wouldn't be able to do this, and it does seem like I must pierce some of the wires---the ones I must check with the throttle body plugged in, and maybe that's all of them. I don't know.
Automotive Expert
No you can back probe the connector

I see the pins labelled 1 to 6 but without a pin-out diagram of the plug or socket (preferably the plug) , I'm unable to do this. Could you provide me with a plug pinout, or if you can describe them, that's good enough. The plug is shaped like a D. I suspect the numbering begins with the top left corner and numbers increase from 1 to 6 clockwise around to the bottom left corner of the D. Is this right? I completely made this up. It's just how I would do it if I designed it. It could start at the bottom left and number counterclockwise to the top left. It's probably one or the other or not. I have no idea. Please describe the pinout or send a picture, but if you send a picture, please note the perspective, for example, "as seen with the plug removed and looking into the plug” or "as you see on the Throttle body" but not both. It's one or the other but so it the direction you count. OK, I've just confused the crap out of myself. In short, I don't feel comfortable poking around without knowing what I'm doing. And are you really telling me to break out the needle test leads? I've done it before on the VVT wires but today, I got a VVT actuator failure. You know, those easy-splice deals, as seen on TV, they don't have flux so the connections don't go well unless you flux the wires first. Live and learn, you know? That's my first time. I wanted to add that I can now drive the car so long as I don't push quickly on the accelerator pedal. The cutouts are becoming a bit rhythmic. If I didn't know better I'd abandon the throttle body wiring, and say that I've got a bad tank of gas, or water got in the tank by any other means. I get really pissed off by shops that don't know jack squat. I had a diagnosis from a reputable shop tell me that the only thing wrong with my engine were the VVT actuators. I tried to explain the difference between the 0021 valve timing advanced errors were a RESULT of the throttle cutting-out suddenly, while my foot is still on the gas. If I'm really careful and immediately lift my foot right when it cuts out, I can prevent the error codes. But I said there's a difference between a P0013 VVT actuator failure cyl 1-4 exhaust. and a P0021 timing advanced error code registered. The P0013 trips on the engine light, the timing error log, does not. I drove all the way to the shop without any ODBII actuator FAILURE codes, and the engine light never came on. But there were timing errors because the engine cuts out while my foot is on the gas. There's no time for the fastest ECU and actuators to prevent those errors. That's why they tell you not to use the ODBII ALONE in diagnosis. Anyway, they never got it. Unbelievable. Anyway, I wanted to tell you also, that I looked at the live air mass signal and it was erratic as crazy. I realize at 600 rom I should get 10 peaks per second but that's not what I'm seeing. Oh, I should take a screenshot and send it. So I have 2 other theories. The bad gas. It idles great...ONLY SOMETIMES. It's very strange. It'll be idling.like garbage and then smooth out. Then, later it'll go back to bad. That supports the bad gas. It's trying to shoot bits of water with the gas? And the other might be that the fuel filter is clogged. It's never been replaced in 85,000 miles. This is why I can ease on the gas but I can't floor it. Maybe? Or maybe the MAS is bad. I looked at it when I replaced the throttle body and it looked like it had fallen apart, so I touched it and it sealed up. It stuck so we'll, I couldn't get it back out. I'm pretty sure that there should not be a pan-shaped metal object that glues in if you poke it with a finger. That's can't be a good sign. I sprayed it with MAS cleaner but if it came undone how would it ever go back on? It falls out in the direction of air flow and when stuck there is such a preview fit that .... I got a new one from Rock Auto parts for a fraction what the dealer charges. I'll try that and put alcohol water absorbing stuff in the tank, for good measure too. Think I Should get a fuel filter. I have no idea where it goes but I'll look it up and I'll look at my new MAS. I bet it's different than what I found that day. If the air mass is erratic as hell, it might make it impossible to get the fuel injectors to operate right. Or the throttle. I'm beginning to suspect these few things and they wouldn't hurt. But to check the wires I need a plug pinout, or TAC pinout. I don't want to go fishing. Let me know what you think of water in the tank. I only drive once a month. I've had this same tank of gas for 9 months. So it might have water in it, it may need a fuel filter or a new MAS meter? Does that all sound harmless, if I try to clear these up? Thank you. I'll look forward to a pin-out.
Automotive Expert
If you scroll up there is a diagram with wire colors

I've got another question. The diagram you sent says that the item on top is the "Powertrain Control Module". Is this located in the box with the ECU? Is it part of the ECU? This is for the 4WD (4-matic) 2003 Passat W8 wagon with the 4WD transmission. You've got the right one? I'm sure you do, just checking. It's such a complex relationship between so many sensors and ..... That tube I mentioned is that I found blown out is 07D-129-482 . I ordered one but it's taking forever to get from Germany but I taped it. Anyway, it goes from the intake manifold to a diaphragm that I think is called the fuel pressure regulator. Could it be that I didn't tape it up well enough? I don't think it would cut the engine out but I'd like to know your opinion. It's located very near the throttle body, if you can find a picture of the throttle body, you'll see this small but very curvy 1/8" ID x 1/4" Od tube (approx). Here's a unrelated question. This engine uses a belt drive for the balancing shafts that keep the engine vibrations under control. It's part # (07D-109-119-A) "[timing belt](/topics-timing-belt-vw/)".. I asked a VW parts shop what the length, width, tooth profile are so I could just find an industrial source. They responded that my engine uses timing chains not belts. They didn't even look up the part.. I have a picture of it from their own website at www.vwpartssource.com but it's just as easy to get a fresh copy from the source. It's a square tooth, probably 3)8" wide and that probably sets the pitch, so the only question is the length. If I know the pitch I could count the teeth to get the length. Anyway, I was wondering if you knew anything about this bekt. They discontinued them, Probably because it is a standard off the shelf component. But without the specs, how could you find a replacement unless you had the old one in your hands? But I really doubt that nobody knows how to replace this, should I need to. They said they called Germany. I doubt that very much. Rock Auto has 3 different belt lengths when I looked there. Come on, only 1 length will work. I just thought you might know, or you'd know someone who knows. It's not the emergency that the engine cut out problem is because I've got to get my car to pass state inspection in Feb. It's not going to pass if it cuts to idle, good or bad idle, while he's testing the braking. It'll be a big problem by then. But I want to be ready for things like the timing belt in case it comes up. I keep a file on my car parts and info about my car. Thanks again. Let me know if you think the problem could be bad fuel, wet fuel, or old fuel or sabotaged fuel. I found yet another huge structural bolt from under my car. Whenever a garage tries scamming me and I refuse to be, I think they get their revenge by either removing these bolts, or they plant other people's excess bolts where they'll fall for me to find as a form of terrorization. My point is that you never know what a person will do. Putting something in the tank is not new. I knew someone who had an ex put sugar in the tank. I can't understand behavior like this. Anyway, could it be the fuel? I don't know. What do you think? I forgot to ask what the best product is for this problem. Old bad gas or water. It doesn't smell varnishy but I don't know. I just thought of the possibility because I drive very seldom these days. I've heard of "an Italian tune up". That's where you drive it for a long drive at high speed to clean things up, get the fluids hit enough to boil out water etc. I can't drive at high speeds at all, but I think that's become a consistent clue. If I ease on the gas very slowly, it actually runs, but 50 tops. How about the accelerator pedal. Is it a potentiometer? Maybe these can get corroded, if it gets wet and sits. It's just an idea. I'm not sure there's a OBDII code for this. What's your opinion of my crazy thoughts. I'm sorry. I'm alone and in pain always, so I can't stop trying to think up causes. I can check the voltages but what if the module is bad? I might find one on eBay but I'd need to know if it's a part of the ECU or if it's somewhere else. Besides, it might be necessary to check the voltages coming out of the module. So please give me hints on where to find this Powertrain Control Module, please. Thank you for just taking the time to consider my issues.
Automotive Expert
It’s ok I can look and find the location for you if you can give me sometime and yes you can check the power and ground which you most likely have but I am just wondering if the ecm is sending the 5 volt signal it needs or if you may have a harness problem just want to get to the bottom of your issue
Automotive Expert
ecm is under the hood looking at the motor upper corner in e-box on driver side by windshield

I understand. I just didn't want to pierce a wire if I don't have to. If I had a diagram of the plug or the mirror image on the throttle body, labelled with numbers so I can check these voltages and responses, That would be essential. I might try reconnecting the ECU and maybe spray it with that corrosion protection stuff for electrical connectors. What do you think of the possibility that my old tank of gas has gone bad or has accumulated water vapor-which condensed once the weather cooled? I only drive once a month to the doctor and he's close: My tank of gas is about 1/4 left but is possibly a year old but I think it's more probable that it's about nine months old. If it had water in it, that would cause engine cut outs, by why does it idle ok? There's no other sensible reason why I can ease the gas up and it does ok, but not when accelerating hard or the way it sputters really bad on right hand turns but not on left ones. Why does it idle so well but only acceleration that aggravates the problem? Why does it seem to be getting better slowly? I'm tempted to empty the gas tank, one way or another, and see if that's not the whole Problem. I actually got a VVT actuator failure code once, on one of those that a rat ate and I used a lot of those easy splice deals. I don't think they have rosin in them so I have measured an intermittent connection on one wire but it stopped being intermittent after I had every line pierced and fooled around with for hours. It only happened once but I should just fix the wires again, but this time, I'll learn from my experience. I do have a question. When I first soldered those actuators together again, it ran like crap so I cut those 4 wires and swapped them around and it ran great I thought, but Is there some way to know which wire goes to which actuator? I'd have to trace each wire (pair) back to the ECU, and it may be clearly labelled. I just don't know because I haven't gotten to the ECU yet to check anything. I haven't found in the service manual yet either. It's a beast of a book and my house and every surface, even in the kitchen is full of various car projects. Also, what did you make of my weak opinion that the MAS is broken? Wouldn't that also cause sudden engine cut-outs to idle? Basically bad engine behavior? I can't quite imagine how the ECU would monitor that device and cause an error code. I imagine there are some problems that still can't be listed as failing on an ODBII scanner. Or maybe it could deduce a failure by the behavior of the voltages on the wires like so many other things. I don't know. I haven't felt well all week so I've made very little progress on my car. I just began to suspect many other things because of so many odd behaviors. Bad gas and water in the gas can produce all kinds of trouble, and if anyone vandalized my car, it wouldn't be the first time and I couldn't trust what's in my tank. What is your response to all of these topics in relation to the crazy throttle that cuts to idle, and when I really push it, EPC codes pop up on the dash and then the throttle becomes inactive except for a whine from a small electric motor that speeds up the more throttle I give it? At first, I thought this was the Actuator in the throttle body with broken gears, but no. Then I figured it's this vacuum pump this engine has. But why is its speed proportionate to the throttle? Bizarre. This is one of those problems each mechanic would follow various theories and codes until he gives up or finds that it's extremely obvious and fixable with $5 of something-. The last 6 time I've been to a shop...nevermind. The last diagnosis I got for this didn't have any relation to the Problem and actually proved that he doesn't even know how to use an ODBII scanner or he doesn't know how an engine works. He four exhaust valve timing errors and said I needed to replace my VVT actuators. I told them that when the throttle is cut while my foot is on the grass, it would always log errors if timing advanced on exhaust valves on both banks. He didn't know the difference between an VVT actuator failure code which lights the engine light like p0013 andd a timing error code that will not light the engine light like p0011 and p0021. which was all he saw. He didn't even drive my car. I drove there by pulling my foot off the gas each time it cut and I found no codes at all, so I drive it around the block a few times aggressively to get some codes for him and I couldn't get the throttle P1021 (I think) throttle actuator failure or ...etc. Even that code can be caused by many different things as I learned by replacing the throttle body. That's why the Instructions with a scanner tells you not to diagnose solely with a scanner. The throttle pedal delays to make valve timing changes. They didn't care to listen. Thanks so much for your thoughtful help with this rubix cube of a throttle problem, or fuel Problem, or.....ok, a car rubix cube.
Automotive Expert
If you feel that gas could be and issue then you can get some fuel treatment and dump into the tank then run down and add another one on a fuel tank and I will be back on fully this afternoon family is leaving so I can get pictures you want ok

On the diagram, I recognize PK-pink and OR-orange and BR-brown, but I don't know what DG is. Dark Green? , did I get them all?. OK, I THINK I can do it now. I get sick so easily. It's been difficult. I noticed that when I replaced the throttle body, The wire took an under and over path which presses the wire again the intake manifold. It didn't affect the performance but I should probably redo the job and tape that connector out of the way so it's not pressed against the intake manifold. Ugh, I'm becoming less able to do car work by the day. I don't know whether I should give it up and get a beer used car or if I should install all the new tune up parts first and try everything I can. I found the perfect infiniti Q50 I've been wanting. Every option I wanted and none that I don't. It'd last the rest of my life and I've almost completed buying it, but it'll take all the money I'm now going through by trying to fix this perplexing Problem. I've got to let them know immediately yet I can't fix everything immediately. I feel very conflicted. Just think if I got the old car out of the way. Right now, every flat area in my house is covered in the remains of various car repair projects. I've got to pass inspection in only a month and a half. If it still runs this bad by then, it won't pass. And if I don't buy the car this week, it'll be too late. And I'll have to start shopping all over and the odds of getting this set of packages is zero. What to do? It seems like the throttle work while under no load and stationary. It's only when I'm driving, taking corners and so forth, that I have trouble, which is why I suspect the gas itself. So finding incorrect voltages will turn up nothing, I know, unless I could test while driving and that's impossible. I bought a MAS and I've got intermittent wires to the VVT actuators too, because I used those cheap wire splicers. I should have just tied the wires and soldered them normally and painted them with insulation instead. Live and learn. It's too much. Then there are the seats an upholstery expert ruined. It's today or never that I fix this stalling Problem in time to keep the option to buy that car. So much pressure. I'm not doing very well. I barely make through each day. I was hoping to restore the car while I still could, but I ran into a rat first. Then after fighting that, this stalling Problem comes along. I'm discouraged. If only I had a buddy to keep me focused. I'll do my best.Oh sorry, you said you're finished with the topic. I should have seen that first. Sorry. You've been great. If I get a fuel product, I don't know which work and which are useless. Do you know? I do know they go from completely useless to pretty good. Without a consumer reports or an expert, I'll pick the wrong one and make the problem work. I have awful luck. Obviously. Can you recommend a brand that actually works on gas that's both old and contaminated with water?You've been great. I just need a recommendation on a fuel conditioner. Is it worth it to try replacing the MAS sensor? Just getting to the ECU is very difficult. I'd like to try the easiest solutions first. My back is all messed up with arthritis. My muscles have an lllness, same conclusion. Could someone help me find the best fuel container/water remover? If I fix the car today I'll call off buying the car.
Automotive Expert
Well Lucas oil products make a great gas treatment or I believe another is called sea foam
Automotive Expert
Try them

The gas in my tank could be old gas, I am familiar with it, but Why does it idle perfectly?  It's barely running, it can crash to idle for a second and bounce back.  It can also trigger that engine light and then drop to a nice idle.     The Electronic Power Control light up when I'm really trying to cause trouble, but I firmly believe that P0013 Actuator failure code is my fault by making 1 bad wire splice.  My first time using those easy-splice deals during an earlier repair.  To diagnose this I bought the needle test leads and tested the continuiy. See, I hooked the actuators to the wrong wires. So I had to cut everything and ADD 4 MORE SPLICES. BAD WORK. SHAME ON ME. But I only get the exhaust code and only when I'm really trying to make it fail.  This resulted in way too many splices. I'll fix all those but these don't cut the throttle to a nice idle. The engine cutting to idle, is the Problem and VVT valves can't do that no matter what. Let me finish describing this Problem because there's something odd about it. I accelerate. Then it cuts to idle. Then It cannot get power, a it sputters cuts, goes a little then cuts. If I turn off the engine, even while it costs, then start it up when necessary. IT RUNS FINE AGAIN especially if I don't try to drive over 30 miles an hour. I get camshaft vibration. So hey, this sounds just like a Problem my dad had. Long story short, he had rust flakes that sat on the bottom of the tank. As he drove, the flakes would start clogging the fuel filter until it just coughed and gagged and quit. That was a big huge Pontiac monster. Anyway, I think this might be my Problem, so I bought some gas restorers and cleaners. If I got sugar in the gas or worse, I may have to drain the tank or maybe go through many filters. WHERE IS THE FUEL FILTER ON MY WAGON. 2003 VW PASSAT W8 WAGONI bought Star-tron and "stay- bil 360"Sta-bil (222376) - 360 prevents corrosion and ethanol damage, fuel stabilizer, cleans fuel system. The reviews lived these 2 by the thousands of reviews. If course I need a cure for my failing body but that's why I need y'all---to make the fixing of the car easier.    I think I'm ready to assume I've got sand or sugar in my tank, and maybe natural causes like bad gas and varnish, maybe A plugged fuel filter to begin with. The car has 85,000 miles and never a change. MORE LIKELY NOW? I'd better get another 2 filters in case it's ful of sugar though. It's got to work now or I'm going to buy a car I cannot afford. Perhaps it idles so well BECAUSE it CAN pump enough gas through the sugar to idle the engine.  Ok, the why do I have complete throttle control so long as it's in nuetral or park????  No load in either case apart from the engine itself. Put in gear and it works until it doesn't. Turn it off and wait for the particles in the filter to meander away, restart and it works, so long 6 I don't need speeds over 30. Sometimes, when it's warm, I can't even go 20. But once it's cut out and I haven't restarted the engine, it will eventually turn on Electronic Power Control light and the engine light. Sounds like starving for gas because of particulates so large that they fall off when I turn off the engine.    PLEASE TELL ME HOW TO LOCATE MY FUEL FILTER.  I know it sounds easy for a nimble guy but my back is so arthritic ..... I bought a Bosch filter according to the charts on Bosch.com.  Maybe I should get another 2 in case it's got signs of debris in it.  Maybe it's better to just go through a few filters. Maybe take off the discharge end of the fter gifts and hang it down so the particulates fall into the filter and stsy. The engine will die, so I'm not sure if I can do that. PLEASE JUST TELL ME WHERE IT IS AND WHAT TOOLS I'LL NEED. thank you. I asked for the pin numbers on a drawing of the plug to the throttle body, either with it disconnected and looking up into the plug, if by looking at the backside 6the uh, it doesn't matter. I've watched my father, and myself rhin many things by poking around without sufficient Instructions. I even tried looking through my shop manual. My muscles and arthritis are so bad I may need to have a shop do it but they will still need to find it. I'll need them to keep it so I can study what falls out of it. I need to do it myself. Garages never understand. Please help. What are the pin numbers on the socket? It's a D shaped socket. Also find where the fuel filter is AND IF THERE'S A BETTER WAY TO FLUSH THE TANK, KEY ME KNOW, PLEASE.That D plug pin numbering on the throttle plug is not in my service manual. It's probably in yours, I hope. Mine misses a lot of things. I'm in such bad shape that I can't hold a vume and read without making my body sore for a week. Progress is slow. Thanks for your help locating the fuel filter. I can't get under my car. It's so low to the ground
Automotive Expert
The earlier VW had the fuel filter on the fire hole but as they got newer a lot of the brands had been putting them into the tank on the pump it’s called a sock but hold on I will look to make sureFrom what I can see the fuel filter is on pass side by the rear door under the car up close to tank and body

2003 VW Passat W8 wagon? The gas filler pipe is just behind the right rear passenger door, so this would be pretty much straight down and under from there. Where is the fuel pump? i'd expect the fuel pump to be close by. It's probably not going to pull a vacuum from far away so there's probably a pump there and the filter may screw directly onto the pump discharge end but I don't know. If there was sand in the gas and clogging the filter behind the pump, I'd expect all it's impeller blades to be shortened. That would also create the same situation of not enough fuel pressure. Isn't there an ODBII code for insufficient fuel pressure? Not that it would hurt to replace the filter and check the fuel system and the fuel itself, maybe drain the fuel even. I think the gas is a year old I haven't gotten any fuel pressure codes. Maybe Also I've been wary of blindly poking around the ECU and even the throttle pins because shorting things is bad, but also, by not knowing which pin is which, I'd be trying to define them backwards. In other words, if I find no 5 volt anywhere, I'll have no idea which wire is the bad one. Look the plug is shaped like a D. If I hold the plug so the pins face me and the flat side is on top, Starting with the top row at the top left corner, number the pins left to right and then drop to the next row and repeat. Please? Or a picture? Something? Please send pictures of where the fuel pump is, There are probably multiple fuel pumps and filters, at least a screen in the tank, which is really a bad place to put much of anything. If you pull the screen out of the tank, the flakes of rust or whatever, will fall off the screen back into the tank and I learn nothing and I fixed nothing and my back is screwed for another 6 months. . So if sugar in the tank is my best theory, I'd really need the Instructions to purge the tank or tanks. Better yet, it'd help to know the fastest way to diagnose this. The more I understand about the piping, the more I'd understand the cause and effect. I'm so super grateful for your help, you just have no idea. Thank you very much. Please send me instructions or a picture of the throttle body pin numbers as they appear in the plug at the throttle. I don't know which pin is pin 5 volts. I know the number, but the pins in the plug aren't numbered, as far as I can tell. Please send pictures of the fuel filter and pump to help me understand what's required before I jack the car up etc. If there are ODBII codes for the fuel system, that'd sure save me some time, or maybe not. I should probably make sure each component in the line is working properly since it's so intermittant. For this, a schematic of the fuel system would really help. It's like those guys that hooked up their ODBII scanner and then blame it all on VVT Actuators. If they understood the causality sequence, they'd know that timing advanced errors are not the fault of the VVT actuators but the way the throttle cuts instantly, that's what's causing those errors. There's no time for them to retard the valve timing. That's not the cause of the Problem but just one effect of the problem. The problem I brought it in for was the cutting if the throttle to idle, while my foot is pressing the gas, driving down the road. So there's an effect, the cutting of the throttle, or what acts exactly like it. I'm trying to piece together the causes which have the sa6 effects as a bad throttle body actuator. If it's a sudden loss of fuel pressure, I'd need to know if it could cause the throttle to cut, not just sputters and gag, but cut like a bad wire. So I've been asking for the pin numbers as seen at the ECU and the throttle. I don't even know if the fuel pressure could drop suddenly without a fuel pressure loss code. Maybe there isn't one, to prevent running out of gas to cause an engine light on the dash. I don't know the cause and effect. That's why I'm asking for this information. Regardless, I'd like to repair the fuel and replace the filter. In which order should I do these 2 things? Replace the filter before I dissolve all that crude and then try to shoot it through the injectors or should I replace the filter first, then dissolve the other crud, most of which will be caught by a new filter? It maybe it doesn't work that way. I'm asking you. I got 3 filters so I'm prepared for any advice. Please tell me the order you'd do it in and why. Thank you so very much. I can't tell you what saving a single activity means in terms of my arthritic pain reduction. Plus your experience. Please help me. Thank you a hundred times. or more
Automotive Expert
well with fuel pressure on a fuel pump you dont always have to get a code meaning that you could have a pump thats being stopped or slowed down by a clogged fuel filter or car could run great at idle or normal driving but as soon as you smash the throttle fast to wide open throttle it could lose pressure under a load and if there is trash in the tank you should pump it out first and get as much as possiable out before changing mulitple filters over and over i will look for and easy axcess if not what you can do is get a small eletric pump for liquid and some tube and install it in the filler neck and pump untill dry then put some fresh gas and change the filter a second time and let me get a diagram for throttle ok

I've seen my gas tank and it's complex. It's 4WD and the gas tank is narrow to go under the spare tire but over the drivetrain. This means that I have no access to the tank that's on the other side of the hump. There's a small pump that pumps gas over the hump when gas gets below a certain point. However, as long as the key is in the ignition and I remove the fuel filter, if I attempt to start the car, then the pump will pump gas out if the tank and the inner pump will pump gas over the hump. I'm getting low on gas as it is. Let me know where the main pump is. This is all a hypothetical that If fuel obstruction is the Problem, then this is the easiest way to get the job done. It'd be better if I drive it first to mix it up, then park in my driveway and pull the fuel filter while the car is idling and just let it die. The pump will continue to empty the tank. But then if I had a pump, I've seen them on Amazon, I'm not sure how the tube would sit in there. It might curl up off the bottom. If only gas tanks were clear, right? So, what's your opinion? I thought if I pulled a filter and backflushed and knocked iit on something, the garbage should fall out if it's large as sand or rust flakes. Then I'd know there was more in the tank but you've given me a good idea. Why not just pull the filter and let the car's pump pump it out into some container. Apparently, it IS getting To the filter to clog it up. S I might jack the far side up to pour the dregs out of the far side tank. Hey, did you say the filter was on the left or right?! For some reason I thought you said it was on the right side. Is that correct? Do I'd jack up the driver's side. If it tilts it enough. After I pull the filter, I'll know if it's garbage. I should anyway, Especially if I remove the rear connection while the engine had been running and then parked while still running remove the back end of the filter first. Oh wait. It depends on whether the filter is before or after the pump. See? A schematic if the fuel system would help me.But with an examination of the first filter, I'll hook up a new filter before running the system to drain the tank and then install a second filter, depending on what the Problem is.
Automotive Expert
It should be the pump then the filter because the fuel would go through the filter then to the injectorsgive me some time I will look as to whisk fuel assy is main and which one is gauge okI want you to lay down your back seat and see if you can see the access cover from pass side ok

if the filter is on the right behind the rear, the pump would have to be back there too. This means that I could use the car's pumps to drain the tank but I'd need to use some restorer so I can drive it effectively or better somewhat. Then when there's only a gallon left, I'll turn the engine over, or maybe just by having the key in and turned, then pump would try to build up a working pressure and really just drain the tank for me. If I remove the filter to do this, then I can examine it to see if there is any garbage or not. If so, I may need to do it once more. The first thing to do is located the things. Second would be to hunt for any kind with 5 volts and another with 12 and make sure they're steady but it does seem more like a fuel problem. It just Shouldn't be hard if I'm hunting for ANY pin with 5 and 12. If only I knew which ones were which, I could test wire continuity. I can't do this if it's a throttle control wire, . Anyway, maybe skip that. just go to the gas and see what's in there to start with. What's in the filter? Then go about either seeing if restorer products will work and if not, keep driving on that tank until it's almost empty and.....if I'm removing a filter, I may as well put 12 vokts on the pump or whichever way, empty the tank, install new filter, put in good gas and drive to gas station for more and see if that's it. If zi do find vandalistic activity, I will put 1 gallon in and drain that. I think the best bet might end up being to install new filters a few times until junk stops falling out of the filters when zi bach flush it and upturn it. There's a vacuum pump on this car. When the engine light is on and I've got the EOC light on the car is completely unresponsive to the accelerator pedal with the one exception that a motor shirts up corresponding with the gas pedal, even when the engine does not. Does this vacuum pump connect to the fuel system? To prime the pump or anything if the sort? zit kinda makes sense by its behavior. These are the only conditions under which I can park the car and press the accelerator pedal down a long ways. I mean, if the EOC hasn't given up, the engine revs up and that sound drowns out this little vacuum pump. It's a curious thing. At first I thought I was hearing the throttle Actuator motor running with detached gearing as if the key popped out. NOPE. It'd be nice to have A SCHEMATIC OF MY FUEL SYSTEM and to know where the filter and pump are physically. This would really help me prepare, understand, avoid screwing something up. etc. Is the pump and the filter connected on the right rear side if the car, underneath and near the edge? I'll try to make sense of it from www.vwpartssource.com or equivalent. Let's compare notes. A d what role does the vacuum pump play? A fuel system schematic would be nice. If you find good pictures of the fuel pump and filter on a 2003 VW Passat W8 wagon, I'd like to see them, and if you can find the pin numbers on the Throttle cable plug , WOW, that'd be really great. I hate guessing when I could short things and ruin the car. A thousand thanks

I think you're right about getting a pump. After thinking about this logically, it does seem like the proper way to do things. It's inconvenient as hell either way but with a pump, it's lesser of 2 evils. And you're right. I still may go through a couple or 3 filters. That's if junk falls out of the original one. Besides, it's never been changed in 85,000 miles and 18 years. This probably works when people drive it a lot and put 120,000 miles on it in 5 to 10 years. But the way mine sits for a month, then drives 10 miles, sits for a month, drives 15 miles etc. That's got to be hard on certain systems. That may even be all this Problem is. The timing was just so close to other repairs. It made me tie other things to that to make a connection to explain it somehow, but there may be enough explanation in Its age and use. It could use (When I'm done), an Italian tune up. That's where you find a long road and drive it for 250 miles, turn around and come back. Something like that. I've heard that this can help but with these gas restorers especially, this would work it through the engine. It might be the thing after I've done all I can, and gave it new plugs and possibly coils too, since I bought them (definitely keeping old parts), and maybe doing it before an oil change. (or after, what do you think?), anyway it's supposed to freshen the seals lubricate what's there and etc. It'll just be nice to drive it again. If it's got a tune up and everything works, it'd make this old man happy. No matter how I change out the gas, but I would need an electric pump. If only I picked a fuel pump for the car from a junk yard. Then I'd have a spare. Let me know what you think that vacuum pump is for. Maybe they're common on newer cars. I have no idea. Thanks so much again.
Automotive Expert
Well a lot of times a vaccum pump is for engine vaccum or booster or a lot or times a vaccum pump is used to heat up the oxygen sensors for the closed loop status

Under the rear seat, there's an access panel on each side. They open to the spare tire compartment on this wagon. What am I supposed to see in there? There's no fuel pump or filter in those access panels but then, I've only see them from the viewpoint of the back. So yeah, I should remove one and see what's in there. The right side? ok. Tomorrow. I'll look for things add fuel restorers. I've been sick on top of broken for weeks. I treated it with antihistamines because I feel so bad anyway I didn't know I was sick. I do feel better now than before I took the antibiotics. So tomorrow is the day.

The pump and filter or one of the other, are probably under the car, but in the space beside the spare tire feature but under that sheet metal. Under the car or possibly in front of the tire well under the car in the side. Well, that would be Exactly under that piece of metal under the access panel, under the seat but under that sheet metal There may be a second access panel if I look. also under the car. No matter how I see it, it ends up under the car but in a gap created by the skate tire well and the frame of the car.. I've looked in there, I remember now. I was looking for a good place for subwoofers. That is a good place. There are even holes beneath but in front on the car underneath the seats in the rear. Like I said though, that space is all spare tire compartment.....that can't be right. I will look. tomorrow. That's the best way to know for sure. Just get out there with tools. Why did you ask? What do you think is beneath this access panel? Another access panel to get to the fuel filter? The pump must be before this, so are they connected?

HEY, I didn't request a new mechanic. Then I hit cancel when it popped up. (Did he quit on me?) Please reconnect me with my mechanic again.Thanks for responding to my question about the vacuum pump.  I get the impression that you don't know what it's for on my car.  I'm forgiving because b because I don't know either.  ::-)  I made the same guesses except for the O2 heaters. Those are electric.      The behavior of my vacuum pump is SIGNIFICANT because the pitch of its whirring sound, its RPM, is controlled by the accelerator pedal, even when the engine is completely unresponsive to the accelerator pedal. This proves that the pedal works, at least. But I think it's important to find out what it's actually used for BECAUSE it's a vacuum intensity COMPLETELY UNRELATED to the intake manifold vacuum. In other words, this suggests that, in some way, it must SUPPORT the engines RPM without being an EFFECT OF the engine's RPM or caused by the RPM. Therefore, it's a good guess that it does help pull fuel to the engine or perhaps something else that supports the engine as it's RPM increases, that is, unless the car has MY problem and the engine is either not getting a control line from the accelerator pedal or for a couple dozen other problems. If it were a part of emissions, crankcase ventilation or something like this, the manifold vacuum is better. Manifold vacuum jumps up because the engine is turning when you lift your foot off the pedal. It closes the throttle valve and the engine acts like an air pump, creating a vacuum DURING DECELERATION. It drops when you press the pedal, opening the throttle, thus decreasing the vacuum, provided that the car doesn't have my problem. The electric vacuum pump acts directly with the pedal position, so it cannot be supporting the manifold vacuum. It most likely supports the engine during RPM acceleration in some way, such as increasing fuel pressure, or fill in the blank \_\_\_\_\_\_\_\_\_\_\_, provided the car doesn't have my problem. HOWEVER, I can't neglect the possibility that the vacuum pump spins up in RPM with accelerator pedal position BECAUSE the engine is idling and NOT responding in any way. In other words, if the engine were working properly, maybe it runs at a constant pace. I honestly can't know, without a friend to use the tube- in the- ear trick to monitor the vacuum pump when I CAN rev up the engine. Maybe it must have some indication that the engine really is under load while the accelerator is being pressed further and further, in order to spin consistently, but these options are pretty darn unlikely. There's just no use for these that .and any sense. Therefore, that leaves the vacuum pump to be something that assists the accelerator pedal in accelerating engine RPM. That's exactly how it acts. Possibilities include assisting the fuel pressure or in operating a diaphragm to push or pull some ignition timing or fill in the blank.\_\_\_\_\_ The next time I feel like throwing it into complete failure (by not lifting my foot when it cuts out and ....(I forgot the next step), then I'll pay attention to the whirring noise when I quickly give it gas and remove it. Perhaps it assists the VVT actuators.....no, forget that. I think it's important to find out what it's for, because it behaved in a very specific way, following the position of the accelerator pedal. That's weird and I'm just curious. I'm supposed to be adding fuel treatment, looking under panels, maybe fixing the seat that the upholsterer put together all wrong and lost all the original hardware. But it's freezing out there and just got over a sinus infection. That got to my lungs because I just thought it was allergy. I took antihistamines. I finally realized I was sick. Took antibiotics, blew clear yellow snot....too much info. Diagnosing people is probably similar to cars. Here's another question. The seat upholsterer didn't plug things in right and he tripped an airbag fault. I go into my OBDII device and clear that out but it keeps coming back. My question is this. Does it refuse to clear, because I have to go to a dealer or someone who can log that airbag fault on my vin number for CARFAX and proper vehicle history? Or is it simply that something is still plugged in wrong? It seems like everything works properly, (except the guy lost my hardware and put it together all wrong.) Electrically it seems fine. I'm going to have to unbolt them and look at exactly what he did won't I? I'm pretty sure that electrically, it's got to be correct now. DOES the code have to be cleared by a professional who can log the fault, or I mean, log the fault were it an accident? They can clear it without logging it but my meaning is that it takes a pro with some key to do it? Is that it?

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