2000 PCM\ECU Question

What would happen if a replacement ECM wasn’t flashed properly and could one from another truck be used for testing? In other words would the truck start and idle with one from a different truck.

you shouldn't have an issue with replacment if you use an untouched pcm from another truck (same year, same transmission, cruise control, etc). I just replaced the pcm on my friend's 95 4.3 CPI with one i pulled out of a wrecked 95 with the same options and it works fine. If someone made a mistake while reflashing the pcm, then you would run into problems.

agree with ZL1. got a used ECM for my '98 s-10 from a junkyard, and it was from a '97 s-10 that had the small cluster, my '98 has the LT trim with full cluster, so no fuel or temp gauge, and battery light is on, although the voltmeter in it works fine, and the used ECM is gettnig the signal from the temp sensor and can read it on a scan tool.

Thanks I am working on a 2000 Blazer that is about due for the marshmallow fix. It died a few weeks back and didn't have spark replaced the PCM and other numerous parts. Got spark back but starts than dies got fuel and if put extra in TB it will run longer. Purchased PCM from ebay $4.99, couldn't go wrong. Same symptoms with it thanks again.

What would happen if a replacement ECM wasn’t flashed properly and could one from another truck be used for testing? In other words would the truck start and idle with one from a different truck.



It kinda depends on how close of a match you got.
The PCM/VCM very seldom goes bad.
But they need to be programed to match your vechical.
I would put the old one back in and go threw the no start basics.
Does it have good spark to all spark plugs and the proper fuel pressure?
Does security light come on key on and go off?
MT

The old one went to NAPA as a core. Please see "2000 Blazer no spark" & "2000 Blazer still won't start" to see all the tests I have done. The security light comes on when the key is turned on and goes out in a few seconds.

The old one went to NAPA as a core. Please see "2000 Blazer no spark" & "2000 Blazer still won't start" to see all the tests I have done. The security light comes on when the key is turned on and goes out in a few seconds.
If it starts and dies in about 2 seconds it is a a anti theft /secuirty problem.

To test for a fuel delivery problem see if it will start and run while spraying in carb cleaner.

The anti theft system if tripped will disable injectors pulse about 2 seconds after start.

It will run while spraying carb cleaner, not too well but will run.

You have a fuel delivery problem.
Confirm and retest for good fuel pressure and then check for lose of injector pulse.

A good scanner would be a big help to find lose of injector pulse.
If you have a start and run for 2-3 seconds it sounds like anti theft is on.
Any add on remote start or anti theft stuff?

Did the Passlock auto learn procedure and it is running for now

Good Glad to hear that.
If you have any other problem or any thing running or working strange you might need to get it reflashed for make and model and engine and transmission.
Good Luck.
MT
And Thanks for posting back how it went.

The one that is installed was flashed by NAPA Thanks for the help.

The one that is installed was flashed by NAPA Thanks for the help.

You are welcome.
The ECM/VCM computer should be good to go then.
Good luck
MT