Crank/Cam Re-Learn Procedure for 2014 Jeep Cherokee

roser601

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Make
Jeep
Model
Cherokee Limited
Year
2014
Miles
67240
Engine
3.2 V6
I have a 2014 Jeep Cherokee Limited 4WD with the 3.2 V6 engine.
It started to run rough and idle rough suddenly while in town and displayed the "check engine light" so I went to my local Auto Zone.
According to trouble codes that they pulled up with their scan tool, they recommended to replace my crank and camshaft sensor.
My question is this-Can the sensors be replaced by me without a special tool to initiate the re-learn procedures or is that repair best left to a shop who has the equipment to do it. My Chilton manual doesn't mention any re-learn procedures that need to be performed after replacement but I was told by a friend that he thought that it would be necessary. Who is right?
 

nickb2

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Hmm, both cam and crank sensors went out at same time? Plz help me elaborate. Codes are fine, but give the hex codes the print out at auto zone gave you, they do give those, or do u have to pay for that?
 

nickb2

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Something is eluding you, hence why u r asking this question.


Ask the right answers, you will get the right answers. This is not a babysitting site, it is advanced site. Post code, will follow through with wiring, and charts, advise, if you listen, follow advice, but mostly logic, we will help u!!


Logic is not always easy when bullshyte is driven in your ear. :cool:

 

roser601

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All you had to do is ask for the codes without the extra comments and I am glad to give them. I am not a professional mechanic and that is why I am here to ask advice from someone who is more knowledgeable than me.
Auto Zone lists codes as follows:
P0300-random misfire detected
P0302-cylinder2 misfire detected
P0202-injector circuit/open-cylinder 2
 

NickD

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Crank and cam sensors consist of a tiny bar magnet with a few turn of a very fine magnet wire around them, easily tested with a scope, even an ohmmeter will show continuity. So simple they rarely go bad, but if they do, in particular both of them, you will have a no start situation. These are the key triggers for both ignition and fuel injectors.

If you have P0202, a definite cause of a misfire, could be as simple as a loose connector connection. Its a coil of wire, an electromagnet, a one ampere pulse of current energizes it at the right time. Again a coil of wire, two pins should a low resistance with an ohmmeter. If an open circuit, has to be replaced, but usually a break in the wire someplace or a broken pin in that PCM connector.

P0300 AND p0202 redundant codes, if that injector circuit is open meaning it ain't getting eneriges by the PCM, that number two cylinder ain't getting any gas of course that will result in a misfire! Random misfire is also redundant.

Surprised you are not getting an oxygen sensor code, it ain't switching, because Cylinder #2 is feeding tons of oxygen, so you would be told by an idiot to also replace your O2 sensor.

But these engines control were made by bean counters, we engineers insisted on an O2 sensor for each sensor, they are cheap, around a buck or so, but not at your dealer with other parts, about 60 times the cost. When that one or maybe even two if a V-6 or 8 sees too much oxygen, it thinks your engine is running lean, so enriches all the other cylinders carboning them up. Putting that raw gas in your catalytic converter will burn it up, more bucks out of your pocket. This is called an automotive chain reaction.

This is telling it like it is.
 

nickb2

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All you had to do is ask for the codes without the extra comments and I am glad to give them.
I often get these

comments, it is not personal, But mostly, I want to help you. The extra comments are just beer and legal canadian weed.


With me it is a hit or miss thing.

Try swapping coils and plugs to narrow down, take note of what is where. It helps diagnose a miss if you dont have live data.

If my comments obfuscated you, know it is not personal. It is just a thing of mine, and I am not willing to change that cuz I know persistence trumps emotion.
 

nickb2

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This is what I love about this site, ppl come, ask questions, we happily oblige, and somehow, after getting down to the nitty gritty, truth comes out. That is where I get to work. ]]

If you have a few bucks to spare, a drb 3 emulator would shine on a laptop for you.
 

Mobile Dan

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P0202-injector circuit/open-cylinder 2
This code would point at the problem, I think. Injector #2 has a failed internal electrical circuit, or the wire harness between computer and injector has failed, or the computer has an internal failure for the injector driver circuit.
Some basic questions...Where is Injector #2 located?...How accessible is it?...can I do a valid visual inspection without disassembly?...Can I use a ohmmeter to compare it to another injector on the engine?...Tip-all injectors should have the same ohm reading, guessing 12-20 ohms.
 
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roser601

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Thanks to all you who are more knowledgeable than I for giving a ton of useful information-it is appreciated!
And thanks to you, nickb2, for the clarification and I didn’t let the comments rankle me.
I am just a crusty old retired union pipefitter who likes to get down to business.
Thanks again for the advice and I’ll see if I can figure it out with the help you all gave me.
 

billr

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Are we all in agreement, this is probably an injector problem, nothing to do with the CKP and CMP sensors/circuits? Use the FLAPS for the free code read, not trouble-shooting advice!

PS: what is with the "sensor relearn" BS? Those are devices with predictable electrical characteristics, essentially simple "on/off" signals. There is nothing to "learn" if the PCM/ICM design isn't very marginal. Oops, is this the fabled "Renix" trigger system? That would explain!
 
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roser601

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I have looked on you tube since my last post and typed in “cranshaft position sensor relearn procedure” for the pentastar 3.2 engine and it shows a video of a guy using what appears to be an expensive scanner to do the procedure. What I gathered is it is used to clear codes and engine check light and is done for all chrysler products.
Since the consensus is that is an injector problem, I will look there—thanks.
 
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