2002 Chevrolet Trailblazer

Engine Performance problem
2002 Chevy Trailblazer 6 cyl Four Wheel Drive Automatic 84000 miles

How do I replace the ECM? I'm not even sure where it is. What do I replace it with? I've seen where I can buy preprogrammed ECM's. But I've also been told I have to have it programmed after install. Thanks in advance
November 28, 2009.

Ok it is not to hard to do. First disconnect the battery positive cable first (and when putting battery cables back on put positive back on last). Now find the PCM it is on the intake plenum front part on the left (drivers) side of the engine. Now remove the bolts that hold the wiring harness on to it and unplug them then loosen the 4 bolts that hold the computer onto the intake and remove it. Replace in reverse order. Now you must take the truck to the dealer to be programmed to you truck. There are no pre-programmed computers for you truck as it needs to be flashed to you truck according to your vin number. I must ask why are you replacing the computer? Here is a pic of the computer and one of how it is mounted on the intake.


How it is attached

Nov 28, 2009.
The " Service Engine Soon" light has been coming on and one time we had a light come on that said something about Reduced Engine Performance. I went to Autozone and they ran a scan when the " Service Engine Soon" light was on. The code was P0601. They said the ECM needed to be replaced. They are telling me if I supply VIN, year, make, model, engine size, OEM number of ECM I will receive correct flash computer. Flash technology unit pre-programmed at the factory

Nov 28, 2009.
This has to do with PCM memory. What is recomended before replacing it is to have it cleared and see if the code comes back. If it does then replacement is needed. With all the proper infor year make model vin number then yes you can get a preprogrammed pcm.

Nov 30, 2009.