Hi from sunny South Africa. Hope 2022 is better than 2021!!

Can anybody on this forum please assist me on alternative ways to code my vehicles VIN into a used / donor PCM??

I have a '97 Grand Cherokee which overnight developed a no-start condition, dead guages and other familiar symptoms.

After months of replacing critical sensors (CPS, CMS) and other components of the ignition cycle with the help of contributors to this excellent forum ...In the end the problem narrowed down to the PCM itself. I obtained a used PCM and the vehicle came back to life .... except that it would only fire once and then immediately die.

I am told that this is because the vehicles VIN needs to be coded into the donor PCM in order for it to run.
This leaves me with a major problem because ... local Jeep Dealers in South Africa state that they are UN-ABLE to do this coding on "old" vehicles.
I find this unbelieveable and hugely disappointing from a global motor brand!

I would appreciate any viable alternatives ways of doing this, as I am now stuck with an in-operative vehicle.

Much appreciated

Huntly

 

You need a new key to communicate with the PCM as the chip inside the key fob is what needs programmed, not the PCM.

 

Thx fb97xj1, will look into that!

 

If SA is anything like Australia, '97 only vehicles had a unique for that year immobilser system, that acts like you describe

I agree with a previous poster that the ignition key and the part of the ignition switch that communicates with the key maybe/is critical.
They are sold as a matched pair by a local specialist Jeep wrecker

There are specialist PCM repair companies in USA that advertise they can do what you want...enter the part number of the PCM into Google

They advertise repair with or without core

Make them aware it is a '97 export model

In Australia, a dead '97 is usually considered unfixable, but I think it depends on whether its the immobiliser.

My mate repaired a dead '97 that had been at a top local auto electrical business for 12months

 

Thx AWG...do you have a link to these USA specialists please. Thx H

 

here is one

Jeep PCM Repair Electronic Control Module Repair - Module Experts

like I said use Google....search term "repair Jeep cherokee XJ PCM" preferably enter the PCM part number, which is printed on the PCM and can be seen without even removing the cover...should be 56041XXX

with XXX being 3 numbers

It may be that a 97 PCM can only be replaced with another 97 PCM.

This is allegedly the situation with 96 PCM.. they dont have immobilisers ..yay!

there are a few posts on repairing PCMs which can be found using the search function on this site...I would not want to try this, unless utterly desperate, even though I a qualified electronics technician...that however is how they are repaired by the specialists

 

Thx AWG.. will try to get in touch with some of them and see if any of them can give me a definite answer on the '97 PCM setup. If I find out anything helpful witll post it back here.

H

 

See response from South African Jeep distributor below!!!
I find it extraordinary that Jeep distributors here expect owners to simply scrap their vehicles if the PCM fails!!



"Good day,

Kindly be advised we have escalated with Stellantis Technical to check if they can assist.

The have advised that this vehicle is a 1997(25 years old)

The diagnostic tool and card for this programming is no longer available so we would not be able to assist, new PCM is also no longer available for these vehicles.

There are outside companies that do key programming, the customer can try to approach one of those companies?

Thank you

Kind regards,

Stellantis Customer Care Team"

 

OK, so local locksmith specialist has coded original VIN into the donor PCM. Vehicle now fires on fuel sprayed into inlet manifold, but ALL injectors have LOW VOLTAGE and so do not fire.

Could this still be another PCM / immobiliser issue?? Could the PCM be cutting the voltage to the injectors, even thought the immobiliser resets properly and the original keys now match the PCM VIN?

Any expert insights would be appreciated. Thx


Vehicle has now been out of commission for over 6 months!!