How to identify stock or modified chip?
 

How do I identify a stock versus modified computer chip?

The reason I am asking is because ever since I purchased my ZR1 the cooling fans come on right away after starting up the car. No codes present, and there is no obvious wiring between the cooling fan relays that I can see to make them run all the time.

So this morning I pulled the chip and wrote down the numbers off it. So far it appears to be stock.

This cooling fan running all the time was ok during the summer but with the fall/winter/spring its annoying and not necessary.

My thinking is that the chip is modified and will turn the fans on all the time. Is it possible to modify a stock computer chip if it turns out to be the oem chip?

Thanks in advance.

Re: How to identify stock or modified chip?
 

What year and what is the PROM ID from the silver label on the PROM itself? I don't know if a modified "stock" PROM would carry the same scan ID as an OE but you could scan it and see.

I believe this should still work by VIN and you will see choices and there will be progressions and the scan ID should be present for each PROM. Depending on the year you could have multiple choices. Do NOT use the back button on your browser, do all selections from inside the program. The program has worked for years, a couple weeks I had a need for it and it didn't work A couple days later it was back and running! This may only run in IE not some other browsers.

https://tis2web.service.gm.com/tis2web

Re: How to identify stock or modified chip?
 

1992 and the prom id is DELCO AZZC2700

Based on the link it appears to be the stock chip....

Re: How to identify stock or modified chip?
 

When you used the drop downs and ID'd the PROM there may have been references to TSB/Bulletins - you can't see them from there any longer but you can research from there. A quick glance at that would seem to indicate it's maybe not the most current release for a '92. You should be able to confirm that using the "drop downs" and the next and information tabs. I believe the most current for that ID would be a 16219916, which is a BPPA.

Re: How to identify stock or modified chip?
 

What does "BPPA" stand for?

Re: How to identify stock or modified chip?
 

My original results came up with:

16172698, 2611, AZZC

Re: How to identify stock or modified chip?
 

BTW,

are you saying I should look to acquire a 16219916 ECM 9991 BPPA/9916 and see if that fixes the problem?

Re: How to identify stock or modified chip?
 

No - but I would have thought the progression might have shown you that BUT the BPPA is the most current. I actually do have a NOS of that PROM and I've posted them for sale before. You should be able to find the "for sale" if you looked. Parts cataloging confirms the part # and I don't have a '92 VIN to see your results but I would have thought it would have confirmed that.

Re: How to identify stock or modified chip?
 

Yes it can be modified. I ran on a prom emulator ostrich II until Dominic worked out all the issues on my highly modified 380. He then reburned the stock chip which is what I am running now. The chip number may mean nothing can you contact the PO he might be able to tell you

Re: How to identify stock or modified chip?
 

The fans coming on suggests that the checksum has been disabled in the calibration. Can be re-done.