Will not start

Tiny
DAVRLAW
  • MEMBER
  • 2005 JEEP GRAND CHEROKEE
  • 4.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 170,000 MILES
My battery went flat. I changed the battery and now the car won’t start. The red immobilizer dot is on when the car is locked. Then when I unlock it with the key it goes off then when I try to start it the red immobilizer dot comes back on.

I have taken it to two mechanics, one auto electrician and they haven’t been able to work it out.

Please help!

Thanks in advance!
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Wednesday, May 15th, 2019 AT 4:05 AM

7 Replies

Tiny
KASEKENNY1
  • EXPERT
Hi,

You should have codes in the system. I am going to guess you have a code for "invalid key." If this is the case then you may need to program new keys or replace the SKREEM module.

I attached the process for programming keys but you will need a scan tool. Most likely you will need new keys because once a key is programmed it cannot be reprogrammed.

I am not sure what happened because if all that happened was you replaced the battery, it should save key information but the light staying on when you put the key in the ignition is telling you that the key you tried to start the vehicle with is not valid.

There could also be an issue with the actual module but the codes in the system will help with this. So let's start there before you replace keys. If you had someone look at it, hopefully they pulled the codes and provided them to you. If not, I am sure they recorded them somewhere so you can just call them and ask what they were. Once you have them, let me know what they are and we can get this figured out. Thanks
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Wednesday, May 15th, 2019 AT 5:02 PM
Tiny
DAVRLAW
  • MEMBER
Thanks very much. I called them and they said it was P0627.

Thanks
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Wednesday, May 15th, 2019 AT 8:55 PM
Tiny
DAVRLAW
  • MEMBER
Also, I d like to add that when it happened the engine wouldn t even attempt to turn over (it made no sound when the key was turned) it went through two mechanics and that never changed. Then after the third mechanic returned the car to me it now attempts to turn over which I find odd.
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Thursday, May 16th, 2019 AT 1:18 AM
Tiny
KASEKENNY1
  • EXPERT
Okay. This code is for a fuel pump circuit issue. This is pretty straight forward electrical diagnosis so I am not sure the level of mechanic you were taking this to but I find it odd that three different ones didn't know how to fix this.

Did they make any repairs or replace any parts?

I included the diagnosis for this code and I think I understand what happened. The first two mechanics had to disarm the security system after the battery was replaced and if they didn't then it would not turn over or do anything when you turn the key. The third guy appears to have done this. Now you have an issue with the fuel pump relay, wiring, ignition switch output, or possibly the PCM.

This test will take you through testing each of these circuits.

Here is a guide on how to check wiring like this:

https://www.2carpros.com/articles/how-to-check-wiring

If you do not want to diagnosis this yourself, I would suggest calling ahead to a shop and ask if they have someone that is confident in diagnosing electrical fuel pump issues. Unfortunately, as you have found, not all mechanics understand how these electrical systems work.

Let me know if you need more assistance or the results of each of these tests and I can help figure out the issue. Thanks
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Thursday, May 16th, 2019 AT 11:30 AM
Tiny
DAVRLAW
  • MEMBER
Thanks Kase Kenny you re really helpful. I don t feel comfortable performing myself so I will check with the mechanic. Does it change anything that a mechanic plugged his computer in it today and it wasn t reading any faults codes? Everytime a mechanic plugs their computer in they erase fault codes.

Thanks again!
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Thursday, May 16th, 2019 AT 11:00 PM
Tiny
KASEKENNY1
  • EXPERT
Well just plugging it in does not erase codes. However, if they are actually erasing them, then that would explain it.

Also, if the codes are not currently active (meaning the issue is not present at that time) then the PCM will self erase some codes. Most stay for an extended time so that a mechanic can review them at a later date. So I would assume the mechanic is actually erasing them.

Please feel free to let me know what a mechanic says if you want some outside advice. Thanks
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Friday, May 17th, 2019 AT 10:33 AM
Tiny
DAVRLAW
  • MEMBER
You re amazing mate! Thanks very much I will keep you posted!

Thanks again!
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Friday, May 17th, 2019 AT 4:19 PM

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