Q: P0123 code 1999 Jeep Wrangler

asked by on March 06, 2017

Jeep threw a p0123 code, so far we've replaced the ecu & throttle position sensor. It idles at normal 800 rpms but when coming to a stop it drops down real low & sometimes stalls out. We hooked a scanner up to it & says the throttle is at 100%

My car has 240000 miles.
My car has an automatic transmission.

Car is stalling Inspection $94.99 - $114.99 Get a Quote

Hi there - this may seem like a wild shot, but I wonder if your torque converter lock-up clutch is failing to release as you coast down, and the engine is having to fight it? I would think you would sense that the engine is under load when this occurs, but perhaps it is only partially disengaging. You have certainly done the logical things diagnosing the throttle. For further diagnostic assistance, I recommend a stalling inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

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 clear the previous HomeLink garage door opener settings?
If you move, or are purchasing a used car, you’ll want to clear the previous HomeLink garage door opener settings before programming your own. You can do this in a few easy steps. Locate the HomeLink garage door buttons. There...
Car died after running the AC
Hi. Running the AC with the engine off will definitely drain your battery. Most automotive batteries are designed to last last about 3-5 years. Being that your vehicle is a 2002, it should be on its 3rd or 4th battery...
Honda N WGN 660 5cc japanese frequent limp home mode
Hello, thanks for writing in about your Honda N WGN. A likely possibility related to the misfiring may be that the car's computer may have tried to recalibrate the fuel supply as a result of the faulty throttle control relay...
My Mercedes Benz Gl450 will tilt to the right quite a lot and the air matic won't work and the front right wheel almost touches the fe
This is likely a compressor issue. The compressor may be faulty or may have a bad connection. This can be tested several ways. You may have a code available from the computer which explains more about the compressor issue. You...
Starts but won't stay running
This may be caused by many different things such as low fuel pressure, low voltage to the fuel injectors, dirty fuel injectors, a vacuum leak, a faulty Oxygen sensor or a dirty or failing idle air control valve. Any of...
Blue smoke from tailpipe
Bluish tinted smoke from the exhaust means that there is an internal oil leak into the combustion chambers from the valve guides, valve stem oil seals and/or the piston rings. Cylinder compression can be tested to get an indication of...
One headlight working - changed the bulb and it didnt work
Hello, thank you for writing in. Several issues will cause faults with the bulbs. If the dim fog light and broken headlight are on the same side, this is a good indicator that there is an electrical wiring issue. Essentially,...

Related articles

How Long Does Clutch Fluid Last?
The The usual answer to this is, forever. Of course, as is the case with many hard and fast answers, there are always exceptions. The reason that your car clutch fluid should last forever is that it’s a closed system....
5 Essential Things to Know About Storing Your Car
Even Even if your car will be sitting for a period of only a few weeks, it’s important that you take steps to store it properly or you will risk having mechanical problems crop up from disuse – some of...
How Long Does a Clutch Slave Cylinder Last?
The The clutch slave cylinder is located on the inside or outside of the transmission. If the slave cylinder is mounted on the outside of the transmission, it is normally attached by two bolts. Every time hydraulic pressure is applied,...