PCM PROBLEM CODE, SENT TO FIX, SAID NOTHING WRONG

My 2006 Jeep Liberty 2.8 CRD 4x4 had code for PCM problem. Sent it 2 different places to diagnose and fix, both said it's fine. My mechanic said may be a problem with wires connecting the PCM. Anyone else have such problems? Or have ideas?

What are the problems?

It kept stopping after driving about 10 minutes. Everything would just shut off.

Any fault codes stored? will it restart immediately?

KJowner said:

Any fault codes stored? will it restart immediately?

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Thank you for responding. I will check with my mechanic. He is at a loss as to what else to try.

If you can give a few more details we can help a bit more, it may be something less expensive than the ECU

My mechanic sent this message in response: "we've tried all that we know to do at this point it's still giving us an issue where it'll shut off intermittently and start working again after it sits for a while, You're more than welcome to come and get it and take it somewheres else maybe they can figure it out but I'm at a standstill on it at this point "
I asked about fault codes. Will see if he responds.
Anyone in south Mississippi/Louisiana area you know of who may be able to work on it?

His response
"There are many fault codes
mass air flow
failure to connect with pcm
Ambient Air temp circuit open
Which all of those codes that are coming up could be from malfunctioning ecm"

MOMEhermits said:

His response
"There are many fault codes
mass air flow
failure to connect with pcm
Ambient Air temp circuit open
Which all of those codes that are coming up could be from malfunctioning ecm"

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3 ideas ( because I can not remember how to spell ‘thoughts’ )
1- marginal battery.
2- bad engine/body grounds
3- green crusties in the common harness that connects all this on top of the engine.

Remember, these are OLD machines. Wiring is always suspect and needs to be examined carefully. Not just like ‘ it looks good’. Give each wire a little tug. You may be surprised when one comes apart in your hand.

Grounds (and missing grounds) always cause electrical gremlins on these jeeps.

Just for fun - if you have a set of jumper cables, try a cable from the negative of the battery and attach the other end to the engine block. That ensures a good ground. Clear your codes and see what you get. Also go negative to body ground. Now both alternatives are covered.

You just might ‘cure’ your problem.

IMO - too many shops rely just on the scan tool and chase codes.

The CRD - I am not familiar with as far as locations of these components. But it is fairly obvious that the ECM/ PCM can not see the Air temp sensor. Is that because the ECM is bad? Are we missing a ground signal? Are we missing reference voltage?

One needs to be skilled / familiar with a multimeter / power probe and chew this up one bite at a time.

Wow, tku for sharing. I've sent it on and will keep you updated .

If it starts up from cold and cuts out when it gets hot, then won't restart until it's cooled down that's a classic crank angle sensor failing, they don't like heat when they get old. Probably worth doing the cam sensor at the same time too, only use Bosch sensors, lots of Chinese junk about...
Ambient air temperature and mass air flow shouldn't stop it running, the air mass is just there to check the egr function, I believe the Ambient air sensor is in the air filter box, mine is earlier so it doesn't have one, Europe got them a few years before you!

Tku much will pass on!

MOMEhermits said:

Tku much will pass on!

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I have the orange motor light since 1 year. I change the side sensor from air box previously and the other at the top of the motor, dirty with motor oil, still no change. Today i replace the air flow sensor but not bosch. Look what i found on the pics. So i trick the connection and i need to reinitialyze but travelling and not now. I will keep you posted.
PS: does anyone can suggest seal solution or inox air box for KJ ?

Just to update those who have been so generous in responding, I think the dud was the mechanic. He said he tried to change the crank shift and it still had the problem, so after 3 months of nothing getting done and them telling me may not be worth fixing, I had it towed elsewhere and the guy fixed it the next morning... Crank Shift.

MOMEhermits said:

Just to update those who have been so generous in responding, I think the dud was the mechanic. He said he tried to change the crank shift and it still had the problem, so after 3 months of nothing getting done and them telling me may not be worth fixing, I had it towed elsewhere and the guy fixed it the next morning... Crank Shift.

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Thanks for the update, the crank angle sensor is often the culprit.

France 16 Olivier said:

I have the orange motor light since 1 year. I change the side sensor from air box previously and the other at the top of the motor, dirty with motor oil, still no change. Today i replace tge air flow sensor but not bosch. Look what i found on the pics. So i trick the connection and i need to reinitialyze but traveling and not now. I will keep you posted.
PS: does anyone can suggest seal solution or inox air box for KJ ?

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You can try a repair with a PVC sleeve.
https://plomberie-online.fr/raccord...ur-evacuation-girpi.html#/31-diametre-o_50_mm

unfortunately not the diameter is 70mm

Try this
https://www.swapland.fr/manchon-sil...hon-70mm-75mm-de-long-noir-4250815803334.html
But it is silicone...

If there is enough space to get the screw clip on then I wouldn't worry, unless you have an air leak it's only cosmetic.
Ebay is full of Jeep being broken for parts so a second hand one would be a quick fix.