Q: Unplugged wires ECM DTC

asked by on September 12, 2016

I purchased a used 4WD truck with the only problems I thought were a dead battery and no air conditioning. My short test drive proved nothing was wrong. So I bought a new battery for it and drove it home. Then the "service engine soon" light came on and the speedometer quit working. Then I saw that the ABS wires were all unplugged for the ECBM. I plugged them in and the ABS warning lights came on and stayed on. I put in a new vehicle speed sensor and engine control module. It didn’t do much good, except the new ECM described a list of DTC codes having to do with the ABS. There is no speed sensor input on either front wheel, erratic rear speed sensor, pump relay out/open, brake switch DTC, etc. I need some advice because this truck is a mess of wires upon further investigation, and it’s above my skill level. I have unplugged plugs up the ying yang under the lower dash beneath the steering wheel and a couple over the AC evaporator. I don’t have whole lot of money either. But do you recommend I take it to a dealer or small repair shop to be fixed?

Electric Problems Inspection $94.99 - $114.99 Get a Quote

Hello. It is a common issue for the ABS control module to go bad on these trucks. Either the modules are ridiculously expensive or they just aren’t available anymore. That is why the connector was unplugged. That is the "cheap" fix. The speedometer issue could very well be the actual cluster itself.

Either that or there is a wiring issue between the sensor and the instrument cluster. Sometimes a new ECM will need to be programmed for everything to work properly. I would focus on getting the speedometer working. For more help tracking down the problem, a certified professional from YourMechanic can inspect the electrical system in your car to let you know what needs repair.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How do I turn on the heated mirrors?
The heated mirrors can help give you visibility out of your side mirrors by eliminating any rain, ice, or condensation. The heated mirrors will automatically turn on when the rear defroster is turned on.
Whooping noise when brakes are applied
Try rotating the tires to see if the tires have a small flat spot. If the noise moves to the front then replace the tires. If the noise stays in the back then have the brake rotors (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-brake-rotor-disc) resurfaced or...
My car is shaking.
Hello. the Diagnostic Trouble Codes would have to be retrieved to begin the diagnosis. Unless the shop retrieved all codes and performed a diagnosis and tested the coils (there are six of them on your engine), what they have told...
why does my car hesitate when I hit the gas and also it has been tested on a computer and all of the oxygen sensors drop to zero
Hello, thank you for writing in. When the oxygen sensors (https://www.yourmechanic.com/services/oxygen-sensor-replacement) read low voltages, the computer thinks the engine is running lean (less fuel than normal) and will try to compensate for it. In doing this, the computer will send...
How much to repair scratch on fender?
Hi there. Unfortunately, YourMechanic.com mobile mechanics do not offer paint / dent repair on vehicle's we service. You would be best served to contact a local paint and auto body shop to receive a bid. Most of the time small...
Knocking in my motor
Unless the engine overheated, the head gasket would not necessarily be damaged by running low on oil. Ticking type noises are usually associated with wear in the valve train. In some cases, low oil pressure will be the cause of...
My car wouldn't revv above 3 rpm and when in motion, it doesn't exceed 2 rpm, as such, it doesn't select gear properly. The car
Hi there. To be honest, this problem could be caused by multiple fuel system or ignition system components. Some common reasons that an engine won't accelerate properly include dirty EGR valve, mass air flow sensors, or clogged fuel injectors /...
a/c only blows cold on the lowest setting and if i turn up the degrees one click it will start blowing hot air
Hi there. What you are describing sounds a lot like an AC compressor issue. However, it could be a relay or switch problem as well that's causing the inconsistent operation of your AC system. The best way to know for...
will a 2008 engine from a pontiac g6 gt fit in my 2006 pontiac g6 gt
The 2006 engine is a LX9 motor and the 2008 engine is a LZ4 motor and they are different. I have never tried to swap these two motors to see the differences and would recommend to replace the motor with...

Related articles

P0007 OBD-II Trouble Code: Fuel Shutoff Valve "A" Control Circuit High
P0007 P0007 code definition The P0007 code is associated with an electrical circuit which connects from your engine computer to your fuel system and is most commonly found on diesel engines. It also may be related to other codes, such...
P0341 OBD-II Trouble Code: Camshaft Position Sensor Circuit Range/Performance
P0341 code definition Camshaft Position Sensor Circuit Range/Performance What the P0341 code means P0341 is an OBD-II generic code that says the...
P2311 OBD-II Trouble Code: Ignition Coil D Secondary Circuit
P2311 P2311 code definition Ignition Coil D Secondary Circuit What the P2311 code means P2311 is an OBD-II generic code for the engine control module (ECM) (https://www.yourmechanic.com/article/what-is-a-vehicle-s-electrical-control-unit) detecting ignition that coil D or the cylinder 4 secondary circuit has low...