husker_shoe

PCM's vary rarely fix these sort of problems, but maybe Mopar has an issue with them? Seems like I'm able to reprogram the PCM for just about any issue other than complete failure

tjwrangler2001

Just had the exact same failure with my 2dr Rubi.. 3500 miles on it and the check engine light came on during a steep descent from 12k ft. Took it into the dealer on Tuesday and they told me 2 things..

1) I have a vacuum pump for the braking system when I tow that jeep that the ground for the pump was attached to the same place as the ground for the O2 sensors. They moved the ground for the pump. Pump is tie wrapped to the tubing for the ABS system on the drivers side front fender. I know the ground wire was fairly short when I installed it so the ground for the O2 sensors have to be close to that area.

2) They flashed the computer as there was some update that fixed a similar issue.

Now.. as for #1.. The pump only runs when the vehicle is being towed. So I really doubt that it was the cause of the issue.

But.. it's been driven several times this week with no check engine lights being thrown..

You decide..

H3What

Update!

Got the jeep back from the dealer last Friday. They replaced the PCM and the downstream #2 O2 sensor and that took care of all the problems. Motor runs better than the day I bought it. Maybe there was a problem with the computer all this time.

tjwrangler2001

another update.. Last Friday it set a P0052 O2 code.. Took it back to the dealer again and this time the tech removed the wire to my pump for the tow brakes.. sheesh... Service mgr didn't necessarily agree, but did state that if it set the code again, he'd get me a different tech..

tjwrangler2001

Jeep threw all 4 codes again this weekend.. Back to the shop tomorrow..

Dwikto

my rubi coded this weekend with those codes as well. it has happened three times now.

1. In big bear also on a steep desent 8500 ft. 4 months ago
2. Lake Havasu when it was 119* out. 2months ago
3. This weekend on the way to the OC Fair only about 80* outside driving surface streets stop and go when it happened. 2 days ago

if any one can shed light please help. i do not want to go waste my time at the dealer if this is a simple fix. i cleared the codes everytime and they stayed off for a good amount of time.

i have looked for a shorting wire, not found anything, no wire on the drive shaft, everything looks tight.

tdshepard

It is a PCM problem. Dealer rplaced mine 1000 miles ago and I have had no more codes. The PCM's were on back order last month so I believe this is a fairly frequent problem...............

Dwikto

thanks for the info, did you also get better MPG when they pulled and replaced your PCM. is that Pollution Control Module or something like that?

tdshepard

I haven't seen an increase in MPG although it is good at 20 mpg in town on the stock X 17" tires and wheels. When I put on my Rubi take off 17" Mudterrains I loose a couple MPG........
Don't know what PCM stands for but that's what the repair invoice says.

TimC

Powertrain Control Module

http://www.aa1car.com/library/pcm.htm