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Chris, Shop Foreman
Category: Jeep
Satisfied Customers: 13758
Experience:  Jeep Certified Master Tech
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1997 Grand cherokee 4.0L . bad pcm R5010380AB. I found a mopar

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1997 Grand cherokee 4.0L . bad pcm R5010380AB. I found a mopar website with all compatibles PCMs. So I went to junk yard and found two PCMS 56044406AD AND 05010380AA BOTH DIDN'T WORK. it starts and dies after a few seconds. the jeep does not have security. it uses a plain black key too. I was thinking that the mecanic was wrong, BUT then He showed me that he could start it using a borrowed computer from a 1998 Grand cherokee (PCM 56041576AA). Engine works good-transmission works good. I already know i can go a dealership and buy the original with the VIN#. I already know that if i find a pcm 56041576aa my jeep runs. I would like to know what modules I can replace to trick the computer and make it run with the either pcms from the junk yard. I know there is another module that tells the jeep its the wrong pcm. lets say, I buy the pcm, all wiring, and every single module in the junk yard my jeep would start. HELP ME!!!

Hello and welcome to just answer. The reason the 2 junkyard PCM's would not work is because they came from Jeeps that did have security alarm. Those PCM's are looking for the "ok to run" message from the security module which your Jeep does not have. So, if you do not want to buy a remanufactured PCM, then you will need to find a good used one that came from a Jeep without the security system.

I hope this information helps, and let me know if you need more assistance with this,



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Customer: replied 7 years ago.
Hello CJ, please let me ask you, how do i know if the computers from the junk yard have security besides testing it on my jeep?, Also,the jeep I got the PCM from, its almost complete. I could take any other parts from it. can i put that security module on my jeep to make it run? why websites show these two pcm from the junkyard to be compatible with mine?? can I bypass this security system to make my fuel pump work?

Well there is no way to tell if a PCM came from another vehicle that had a security system. It works like this: If a pcm is installed into a vehicle that does not have security alarm, then it will never look for a SAM module signal. But once a PCM is installed into a vehicle that does have security, then it will become "married" to the SAM module and will always look for the signal from the SAM module. It can not be changed after it becomes married. So the PCMs that you have are the correct ones, but were installed in vehicles that had SAM modules and need to see that "ok to run" signal from it in order to run. Now your question about installing the SAM module from the donor Jeep may work if the wiring harness and connector is there in your Jeep. It seems to me that you would be better off just getting a "fresh" re manufactured PCM from the auto parts store and be done with this asap.