If you mean the pcm, then its inside the air filter box on the bottom
The ECU is in the engine compartment on a 2002 Pontiac Grand Am. It is the sensor behind the converter.
Under the air filter in the air cleaner box
the front passager kick panel
Yes, as long as it is a 3800 Series II V6. Not a Series I. A Series II will say Series II on the engine cover. If it is a Series one it would fit because it is the same size, but I do not know if it will work with the Grand Prix's ECU and transaxle.
Sometimes disconnecting the battery (Black Neg-- Cable) for 20 minutes will re-set the security, What it does is set the ECU back to factory default settings, and the car will run rough for a few miles, while the ECU 're-learns"
Where is the ECU on a 2002 Dodge Grand Caravan
You can't as it has no governor. Speed is controlled by the ECU.
The 2002 Ford Windstar ECU can be found on the firewall in the engine compartment. The ECU will be on the drivers side of the firewall.
It has no governor. Speed is controlled by the ECU. To change it you would have to reprogram the ECU.
under the antifreeze compartment
Behind the glove box.
under the air cleaner box