Possible PCM issue????

[Cdoc101]

Hi,
I had an issue about a month and a half ago when I was driving my jeep and the dealer can’t figure out what’s going on with my jeep. I was driving the jeep and all of sudden I had a hesitation in power, check engine light came on for a minute. I pulled over, turned the Jeep off and when I restarted everything seemed fine. After about a week of not driving it, my wife started it up in the morning and drove it down the street and the jeep was sputtering, the air from the vents were erratic. When she came home I started the jeep and sure enough the check engine light came on. Took it to the dealer and they advised that it was throwing a P0305 code and that there was a stored P2314 code that may have came on before. They swapped ignition coils and it seemed to run okay for a few days and then the same thing happened. Took it back to the dealer and it was throwing the same P0305 code but they claimed this time it wasn’t misfiring. I called them up and asked them to check the PCM. They called me back and said it wasn’t the PCM and they can’t get the vehicle to throw a code. They have put about 100 miles on it but can’t figure it out. I still feel like there is something going on with the PCM………..anyone have a similar issue or any advice????

 

[guruman]

FWIW, I had issues with my old JKRU. It kept throwing O2 sensor codes, despite replacing the sensors and cats multiple times.

I had setup the Torque app on a tablet and mounted in the Jeep to monitor the O2 sensors over the long-term. And it wasn't until I was doing some wiring, and left the key on while digging around in the engine bay, and the O2 sensor codes alerted on the tablet...... the engine was not running. I was able to reproduce it by moving the main harness where it attached to the PCM.

Figuring it was either the harness or the PCM. I had the entire main engine harness replaced. But the problem remained. Which left only the PCM to blame.

I ordered a new pre-programmed PCM that took 10 minutes to swap, and the problem never returned.

Just because the PCM passed its tests, does not mean that it cannot have an intermittent connection issue internally, or at the harness plug.

That being said, I feel that a faulty PCM is less likely, but the list is finite. spark plug> coil> coil harness/connector> main engine harness> PCM (or something close to this).

If it keeps doing it, keep presenting it to the dealer and documenting the process.

I'd ask them to fire up the old parts cannon and replace the entire chain of parts, followed with a not-so-veiled inquiry about how many times does a problem need to appear for it to be considered a "lemon" under the law....

Good luck.

 

[Cdoc101]

FWIW, I had issues with my old JKRU. It kept throwing O2 sensor codes, despite replacing the sensors and cats multiple times.

I had setup the Torque app on a tablet and mounted in the Jeep to monitor the O2 sensors over the long-term. And it wasn't until I was doing some wiring, and left the key on while digging around in the engine bay, and the O2 sensor codes alerted on the tablet...... the engine was not running. I was able to reproduce it by moving the main harness where it attached to the PCM.

Figuring it was either the harness or the PCM. I had the entire main engine harness replaced. But the problem remained. Which left only the PCM to blame.

I ordered a new pre-programmed PCM that took 10 minutes to swap, and the problem never returned.

Just because the PCM passed its tests, does not mean that it cannot have an intermittent connection issue internally, or at the harness plug.

That being said, I feel that a faulty PCM is less likely, but the list is finite. spark plug> coil> coil harness/connector> main engine harness> PCM (or something close to this).

If it keeps doing it, keep presenting it to the dealer and documenting the process.

I'd ask them to fire up the old parts cannon and replace the entire chain of parts, followed with a not-so-veiled inquiry about how many times does a problem need to appear for it to be considered a "lemon" under the law....

Good luck.

Just got a call from the dealer and they claimed that they called Chrysler and Chrysler advised them to check all the wiring, just as you did. If that doesn’t resolve the issue then it might be the PCM. Fingers crossed they figure it out one way or another.

I appreciate you sharing your experience. I didn’t consider the wiring. The frustrating part is that I want to try all sorts of troubleshooting diagnostics but since it’s under warranty I don’t want to void anything so I am leaving it in their hands.

 

[RadMan]

Just got a call from the dealer and they claimed that they called Chrysler and Chrysler advised them to check all the wiring, just as you did. If that doesn’t resolve the issue then it might be the PCM. Fingers crossed they figure it out one way or another.

I appreciate you sharing your experience. I didn’t consider the wiring. The frustrating part is that I want to try all sorts of troubleshooting diagnostics but since it’s under warranty I don’t want to void anything so I am leaving it in their hands.

I did a lot of research prior to taking delivery of my 392 and one of the common problems I saw was the engine harness not being properly attached to the firewall. Sure enough, when I picked up my Jeep, the large harness behind the motor on the passenger side was just hanging loosely and almost touching the exhaust manifold. The harness had a clip that was meant to mount on a stud on the firewall, but it was never clipped in place. I'd look at that harness and the main grounds that bolt to the frame near the right front passenger tire. I've seen several people have problems with those grounds coming loose.

 

[Cdoc101]

I did a lot of research prior to taking delivery of my 392 and one of the common problems I saw was the engine harness not being properly attached to the firewall. Sure enough, when I picked up my Jeep, the large harness behind the motor on the passenger side was just hanging loosely and almost touching the exhaust manifold. The harness had a clip that was meant to mount on a stud on the firewall, but it was never clipped in place. I'd look at that harness and the main grounds that bolt to the frame near the right front passenger tire. I've seen several people have problems with those grounds coming loose.

Thanks……and this is why I joined this forum. I appreciate all of the help!

 

[RadMan]

Thanks……and this is why I joined this forum. I appreciate all of the help!

You're welcome! I hope they figure it out quickly. Keep us updated.

 

[Earl 392]

Thanks……and this is why I joined this forum. I appreciate all of the help!

Also some ground studs in back of passenger headlight a bit difficult to get to but worth a shot. I think that’s also where power steering pump is grounded

 

[prodriquez]

I’d also contact @JeepCares and open a case with Jeep so they can coordinate with Jeep.

 

[JeepCares]

Hi,
I had an issue about a month and a half ago when I was driving my jeep and the dealer can’t figure out what’s going on with my jeep. I was driving the jeep and all of sudden I had a hesitation in power, check engine light came on for a minute. I pulled over, turned the Jeep off and when I restarted everything seemed fine. After about a week of not driving it, my wife started it up in the morning and drove it down the street and the jeep was sputtering, the air from the vents were erratic. When she came home I started the jeep and sure enough the check engine light came on. Took it to the dealer and they advised that it was throwing a P0305 code and that there was a stored P2314 code that may have came on before. They swapped ignition coils and it seemed to run okay for a few days and then the same thing happened. Took it back to the dealer and it was throwing the same P0305 code but they claimed this time it wasn’t misfiring. I called them up and asked them to check the PCM. They called me back and said it wasn’t the PCM and they can’t get the vehicle to throw a code. They have put about 100 miles on it but can’t figure it out. I still feel like there is something going on with the PCM………..anyone have a similar issue or any advice????

Hi there, please send us a private message with your VIN and contact information so we can look into this for you.

Yenori
Jeep Cares

 

[L3FTY]

Had a very similar situation in October, the great white boat anchor left me stranded on Pott's Mountain in VA. Took the dealership 35 days to sort it out. Turns out was a pinched harness under the dash. As an engineer myself, I was underwhelmed with the support (lack thereof) from the oem engineering team. I made the suggestion that the tech should shoot loops and isolate sections to narrow down to the location after the dealership threw everything but the kitchen sink at it. The Dealership was truly stellar BTW!
I can't get the photos to load unfortunately. Regardless, I hope the best for you and perhaps the tech should consider a similar approach. Keep us posted please.

 

[L3FTY]

Also some ground studs in back of passenger headlight a bit difficult to get to but worth a shot. I think that’s also where power steering pump is grounded

Yes! This great place to start! I actually checked every ground I could find whilst on the trail at the camp site.