Have Jeep Questions? Ask a Jeep Repair Expert for Answers
Hello and welcome! My name is ***** ***** I can assist you with your question. Are you saying sometimes it does not start? Does it crank over and not start or does it not even crank over at all? Can I start by getting your VIN or engine size?
Thank you for that information. So does the starter engadge? Does it start and then stall out? Does the check engine light come on with the key on?
Ok, this is most likley a bad PCM. Sometimes the cam or crank sensor will short out pulling the PCM off line so be sure to check those as well. If they check out good, all of the powers and grounds need to be checked going into the PCM with the key on. If they all check out good, the PCM is bad and will need to be replaced.
I am glad I can help! Please dont forget to honor your good faith deposit by rating my answer as "excellent service" for assiting you today. Please let me know if you have any further questions.
Ok, then they overlooked something.. most likely an input to the PCM like I mentioned.
Please call me so we can talk. I will explain everything.
YES, phone calls are extra.
You will get so much more out of this conversation over the phone.
I am waiting for your phone call
If the PCM was replaced, it obvioulsy is not the problem. I can explain everything over the phone.
Ok, no problem. If the PCM is not communicating and it has already been replaced, then it is either being shorted out (like I mentioned) or it is missing an input (like I mentioned)
I am positive
Because this problem is happening intermittantly.
Sometimes the PCM is being affected.. and sometimes not.
Therefore, it runs sometimes, and sometimes not.
I am sorry but I dont understand you question. Can you please repeat it?
No, it does not work that way. You need to check the inputs first to see what it is missing and then go from there. Since it has been replaced already, it should not need to get replaced again.
I am glad I can help! Please dont forget to honor your good faith deposit by rating my answer for assisting you today. It has been a pleasure working with you. Please feel free to request me in the future or request a phone call if you would like to speak on the phone.
If the problem was the PCM, then no, it would not to the same thing when this happens. Because the PCM would have fixed the root cause. It does the same thing because the same problem is still happening. No, it cannot run without the PCM.
YES, that is a possibility
I am sorry but I dont understand your question?
YES, the wiring can do the same.
The same thing I have been telling you. Check the inputs to the PCM when this happens.
The inputs power up the PCM. The PCM cannot work if it is missing an input.
Excellent! Please tell me which inputs were checked.
And of couse the results/readings of the test.
You need to get more details.
YES, at least the powers and grounds.
Full battery voltage and good grounds going in. Your mechanic should know this.. especially if he just got done telling you they are "100%"
You know we could have covered this hours ago over the phone. YES, I can tell you.. give me a bit while I gather this info
In addition, he should have checked this if everything was "100%"
The powers are pins 11, 12 and 29. This is on the C1 connector at the PCM.The grounds are pins 9, and 18. This is on the C1 connector at the PCM.
The PCM should NEVER be replaced EVER EVER EVER be replaced without these inputs checked and verified as good. This needs to be done BEFORE the PCM gets replaced.
Based on what your telling me, (or not telling me), this was NOT done.
Something tells me that I or both of us is not getting the full story here.
OR the mechanic simply did not follow through properly and check these things before the PCM was replaced.
I dont know because I am not there. You will need to ask him the inputs he checked. If he hesitates for a minute, then I would be very suspicious/skeptical of his diagnose skills.
If the PCM is not communicating and it has been replaced, provided the new one you got it good, but the PCM is still not communicating, then the PCM is missing an input. It is as simple as that. I will be looking forward to your reply!
Lol, yes, that is what I have been trying to tell you since 9 AM this morning.
Sounds like a plan. Now will you rate my service?
No, we can still continue this conversation even after you rate my answer.
Hello! It's Amedee from just answer. I am just checking in to see if you had a chance to speak with the mechanic?
Ok, sounds good. Keep me posted.
It's Amedee from just answer. I am just checking in to see how things turned out and if you need further assistance. Please let me know.
"Seems"? Something is being overlooked. Please accept my offer and call me
We will be able to communicate better over the phone
Ok, was the BUS circuit checked?
How am I supposed to help if you dont respond back?
Obvioulsy the BUS circuit has not been checked.
At least not correctly. If it were, then a diagnoses would have pinpointed the problem.
All of them
With a lab scope
Hello and sorry for the delay! A good driveablity tech should have a lab scope. However, if not, then he will need to use a scanner and check for communication to all modules on board the vehicle. Most likley he will find an issue with more modules than just the PCM. Again, your mechanic should know all of this.
A lot of times the instrument cluster itself goes bad causing both of these issues.
And if your mechanic has been in the business for a while, he would know that this is a very common issue on these vehicles.
Hello! It's Amedee from just answer. I am just checking in to see how things are going and to see if you need any further assistance?
YES, it is possible to fix it yourself. However, it may not be easy to diagnose and fix depending on what is wrong with the vehicle and what tools you do or do not have access to..