JEEP 2.7 CRD computer problems

[Lodewijk]

I bougth a used Jeep Grand cherokee 2.7 CRD 2003 when after a half year the car didn't drive anymore. I could start it but could not use the accelerator pedall. The PCM could not be reset.
The garage suggested to place a newe PCM. So we did. After half a year it happened again. Again new PCM and we tried to find where a high voltage could come from that would blow the PCM. We changed the start enginge.

Now after two weeks drive, exactly the same again!!!

DTC's are P0100, P115, P190, P235, P1608 P2120, P2125.

Somebody any ideas where this high voltage could come from? we are thinking of replacing the generator??

thanks in advance for any reply!

 

[valeriu]

Hi, I think I found the problem with the P2120 & P2125 codes on some other forums. I have the same problem by the way...
Apparently it's a problem with the connectors in the TAC module. Either they need cleaning or some pins get bent inside after a while and need straightening, patience is required for this job.
I will do it and let you know how it went

 

[jimbob2001]

Sounds like an Issue with PCM's. OBD Code--P1608 is the KEY here. This Code indicates a : LOSS of Serial Communicàtions. The PCM is NOT Talking to ANY devices! NOT GOOD. This NORMALLY indicates an Internal Computer Issue! (Bad PCM) Next question --- What would CAUSE the PCM to Fail? ONLY Two things ---- 1. Excessive HEAT on the PCM. OR --- 2. EXCESSIVE VOLTAGE. (Greater than 15V Assuming there are NO Heat Sources Near the PCM? True? Then CHECK. Alternator and. VOLTAGE REGULATOR!! Is your CHARGING VOLTAGE approx - 14VDC? NO Excessive Voltage or Voltage SPIKES??? If you EVEN suspect this-- I would change out the ALT~REGULATOR! PCM's (plural) Can get some what expensive! I would ADVISE getting the Charging System Checked out. Good Luck. Keep us Posted. JB

 

[jimbob2001]

Just wondering IF the Poster on this Thread --- Got his Jeep PCM problem sorted out?? Interesting Problem! Anybody Know? A follow-up Comment to the Post I made on this PCM Problem. Besides the Excessive HEAT and Voltage I Mentioned--- It is important to Remember that PCM's (essentially a computer) -- MUST be correctly Installed. I.E. --- Proper GROUNDING --- ALL Heat SINKS correctly Installed-- and ESD Precautions Observed. These things WILL Aide in the LIFE of your NEW PCM! Comments? JB

 

[Lodewijk]

Thanks for the reaction.

I had to sell my Jeep unfortunately because our family couldn't do without a car. My garage worked on the problem and had the generator thoroughly tested and send the computer to an expert.
The expert told that it could indeed only be excessive voltage that blew the PCM so it had to be the generator.
So a new PCM(3th) is build in, and the generator has been replaced als well as some small relais.
The voltage regulator seems to be build in the PCM?

The car is now driving again and it is for sale. We don't know if the car can be trusted now for 100%, we will see!

thanks,

 

[jimbob2001]

YES --- On Many Jeep Models --- The Voltage Regulator is BUILT-IN to the PCM. Glad You got it all straightened out. It is Unfortunate that you NEED to Sell the Jeep. But, I can understand why you feel this is necessary. If it is any consolation --- Your Problem was a Fairly Rare One --- We seldom see a Problem ---Where MULTIPLE PCM's Fail. (In a Row) Who ever Worked on the JEEP the FIRST time it Failed --- SHOULD have asked the QUESTION--- WHY DID this PCM Fail? Then, AFTER Installing the NEW PCM--- He SHOULD have checked FOR: 1. Excessive VOLTAGE or HEAT Sources! He did NOT do this --- and YOU paid the PRICE --- Perhaps selling the JEEP --- Is your best Course of Action at this Point. I'm SURE you DON't want any MORE Problems!? -- Good Luck! JB

 

[valeriu]

hi all, the P2125&P2120 appeared on my jeep due to Shifter Lever Assembly voltage problems code P0702. Needed new SLA module only found at dealers unfortunately, vvvv expensive. so hopefully will fix the problem for good