behind the gove box, use 7mm to remove. PCM clips into plastic bracket.
Inside the car, under the dash, under the glove compartment. It's a silver box with 3 electrical connectors on it.
You would have to send the pcm out for a reflash at "intense racing". They also do other upgrades to the pcm will reflashing
On the dashboard
It is in the air intake box at the front of the car.....one of the easiest PCM's to get to, but no GM dealer seems to want to tell you that.
Powertrain Control Module (PCM)
Yes
under passenger side kick panel
The charge from the alternator to the battery is regulated by the On-Board Computer System (mainly referred to as the PCM or ECU). I had a problem with my Riviera not charging the battery and blowing out alternators by sending feedback to them. I would recommend seeking an OEM re-manufactured or replacement computer. They are not easy to install so it's up to you if you want to try. I would recomment a mechanic so it is warrantied.
The PCM (or ECM) is located on the interior of the car on the passenger side. To access the PCM/ECM remove the kick panel just beneath the glove box and it is right there. Disconnect the three electrical harnesses and and sucuritity clip and it's out.
Under the dashboard , behind the glove box, passenger side.
the Pcm is located to the front right of the engine compartment under the washer fill tube and to the right of the battery
The PCM is located under/behind the dash on passenger side of vehicle. It is very near the passenger side door.
Open the glovebox and pull rubber stops forward so box drops completly.You'll need a flashlight to see the fuse box located on the sidewall to the right of the pcm. its not easy to get to but needlenose pliers help w/ removing fuses