Recently started having random stall and no start issues on my 2001 Xj Sport
​I started electrical testing my TPS when a CEL code came up P0122. I figured the wires must be loose and I loosened them more.

I pulled out the wiring diagram and continuity tested all of the wires going to and from the TPS, the TCM and the PCM. All wires tested fine. I ever compared results to s working XJ and got the same resistance.

I also put in a new sensor and the codes still come back after clearing it.

Lastly, I didn't touch it for about 2 weeks and came back to a completely dead battery. Now I'm wondering if my electrical issues was just the battery going bad?

I'm going to pick up a new battery. What other tests can I perform to pinpoint my issue? I also pulled the horn relay to exclude the possibility of the clock spring being shorted.

Any advice you guys may have Is greatly appreciated.

 

A bad battery will definitely cause running problems. A bad battery can also drain itself. Start there. Make sure your terminals and cables are in excellent shape.

It never hurts to clean up your grounds. See my sig, #1.

 

I went ahead and cleaned the grounds before getting a new battery. I don't think this was the cause of my issue because I found something odd when doing more continuity tests.

There is continuity between wires K7 (5v signal) and wires K167 (sensor ground). It doesn't affect all the sensors but most of them (which have the sensor ground k167 wire) show a slight resistance between the two wires.

My best guess is the K7 is exposed and shorting to ground. I just have no clue where.

Are there any tips to finding the location of the short?

 

Problem solved (99% sure). It ended up being a short in the MAP Sensor. So this thread will serve as a reference for anybody else because there seems to be a lot of people with this same problem unsolved. Here's what I did.

CEL P0122 and P0123 refers to voltage to TPS either to low or too high.

I started by backprobing the TPS to test it while the ignition switch is on. Voltages for each of the 3 wires should be with in a certain range (specified in factory service manual). My results were inconsistent. Manual says to replace. CEL still comes on with same codes.

I cleaned all my grounds and did a visual inspection. Everything checked out.

To test for broken wires along the circuit I continuity tested from the TPS to the PCM C1. These diagrams can be found in the factory service manual. I also tested from the sensor to connector c107. And from C107 to the PCM. All of the wires passed the continuity test which means no wires are broken.

This lead me to believe the wires were touching but not broken. To figure this out, I continuity tested between two of the 3 wires going to the TPS. Since these are all supposed to be separate wires there be no resistance reading. The test showed that my 5V(+ line and K167 (ground) were shorting somewhere.

To find the short I pulled up the wiring diagram again. With C107 disconnected, I could eliminate any wires or sensors on that side. I placed each probe on each of the shorted wires (K7 and K167) and got a continuity of .8. I then looked at my wiring diagram to figure out which sensors those wires run through. I then started pulling off harnesses going to those sensors until that resistance reading disappeared. When I pulled the map sensor...BINGO all of my continuity tests were reading normal.

Good luck

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Excellent work!

And thanks for reporting back. It helps others down the road.