Gremlins in my TPS

[JOHNR]

My name is John - I am a new Forum member. I have a 2003 Jeep Wrangler 2.4L DOHC (140k miles). It has been a great little Jeep until a recent problem I cannot solve. I'm hoping a Forum member can help.
The Jeep sat in my garage for 4 months untouched while I attended to some medical issues. When I did start it up, the Engine Service Light came on. OBD code is PO123 (TPS). I'm on my second new one (Mopar this time). I have verified wiring - TPS through the computer black plug pins. The local Jeep dealer said, after his tests, that the problem was the computer. I sent the computer to WranglerFix - they found no problems with the computer. I replaced the Idle Air motor - the engine STILL dies when you release the throttle. Only modification to the Jeep from original is a JEEP AIR AC system I installed 2 years ago. It is working fine as well as turn signals (no cruise control), steering, lights radio etc. I'm at a loss. Any advice greatly appreciated. John

 

[macleanflood]

Mice? You verified pin to pin on wiring...I'd deloom that harness because pin to pin continuity doesn't mean there isn't a short to something else.

-Mac

 

[ItchyDong]

 

[ItchyDong]

I need to redo this video and add that the only true way to verify that the PCM is receiving and interpreting these voltages correctly is to hook up a scan tool and watch live data. It’s one thing to have all the voltages act right at the sensor, it’s another to verify it’s being interpreted correctly. Mark already did that for you, and the healthy bias voltage kind of does it, but it doesn’t show the interpretation. So, that’s a project for another day.

I’m thinking about going through and making videos for every DTC. Too many guys are prematurely ripping apart harnesses or blindly cleaning grounds before testing.

 

[JOHNR]

I need to redo this video and add that the only true way to verify that the PCM is receiving and interpreting these voltages correctly is to hook up a scan tool and watch live data. It’s one thing to have all the voltages act right at the sensor, it’s another to verify it’s being interpreted correctly. Mark already did that for you, and the healthy bias voltage kind of does it, but it doesn’t show the interpretation. So, that’s a project for another day.

I’m thinking about going through and making videos for every DTC. Too many guys are prematurely ripping apart harnesses or blindly cleaning grounds before testing.

That would be appreciated. I'm not an electronics expert and I still don't know how to fix this issue. There are no mice and none of the wiring seems to be disturbed. This apparently started with the Jeep sitting still — almost like a component at end of life. Seems unusual for solid state things though.
John

 

[hear]

I’m thinking about going through and making videos for every DTC. Too many guys are prematurely ripping apart harnesses or blindly cleaning grounds before testing.

I’ve had the same idea. Show how to verify the signals/grounds and bench test the various sensors. I got as far as doing the cam sensor, and then I never found time to do another. Turns out doing good videos is really hard & time consuming.

Well, what I mean to say is doing crappy videos is hard and time consuming. I can only imagine that doing a better job would be even harder.