Hi gang!
Been a minute since I posted something on the forum. After my last posts my father-in-law was able to enjoy his Jeep until recently it started acting up again. The phenomenon is the following: while cruising, he feels a sudden short jolt (I'm guessing gearbox) after which the check engine light comes on. When he turns off the car and turns it on again, the check engine light is gone. He's a really relaxed driver (read: sloooow), so he unfortunately doesn't know/feel the difference between a car stuck in limp mode or not. I haven't been able to reproduce the issue driving it myself yet. It has the following codes (some likely unrelated).
Engine Control Module:
P0110 Intake Air Temperature Sensor Circuit (it's in the mass airflow sensor I read, which I already replaced, so I guess it's not the sensor, haven't read the live data yet with WJDiag Pro)
P0702 Transmission Control (generic code for issues with the transmission?)
P0190 Fuel Pressure Sensor Circuit Malfunction (haven't replaced the sensor yet, also haven't read the live data yet with WJDiag Pro)
P0340 CMP Position Sensor Circuit (replaced the sensor already, didn't fix it)
Transmission Control Module:
P240D ID 44 Engine T-Case Switch Message
I tried to replace the t-case 5-position sensor; bought a new, but apparently faulty, unit from a German jeep shop (couldn't find it anywhere else at the time), but it immediately threw a P2502, transmission slipping. When I measured the resistance at the ECM (between pins 29-21) I noticed that both 4Lo and 4AllTime read 60 Ohm, neutral 200 Ohm. I then checked the old sensor and it read roughly 60/200/400/700/1200 Ohm according to spec, so I put it back and the P2502 disappeared. So it's NOT the sensor (unless it fails when hot or so) and NOT the wiring (unless it rubbed through somewhere and shorts while driving).
I also found a shifter-PCB that could be the cause of the P0702, but not sure if that causes this jolt? Either way at >350EUR for this PCB, I'm done firing the parts cannon at this thing, it's getting ridiculous.
I read the codes both when the MIL was illuminated and when it was not, the codes all came back exactly the same, so the code triggering the MIL to turn on disappears again? I would guess that it would get saved?
Could use some help figuring out this issue.
Oh, and if you have tips on the other codes, always welcome as well!
Cheers
Nic
