A failing or damaged computer on a 2000 Chevrolet Cavalier can render the vehicle inoperable or complicate vital engine processes. However, the computer, called a Powertrain Control Module (PCM), can be changed by most backyard mechanics. When obtaining a replacement PCM, it is imperative to get a unit from a model of the same year, with the same engine, transmission and vehicle options. Changing the PCM is a fairly simple process if you have a matching unit. Otherwise the unit must be reprogrammed at an authorized service center that has a GM Tech 1 Scan tool.
Lift the front of the vehicle with an automotive jack and support it with jack stands.
Remove the lug nuts with a ratchet wrench and remove the driver's side wheel.
Use a ratchet wrench to remove the fasteners that hold the splash shield to the fender on the driver's side of the vehicle and remove the splash shield from the vehicle.
Disconnect the electrical harness to the car horn, remove the bolt on the rear of the horn with a ratchet wrench, and remove the horn from the vehicle.
Unplug the electrical connectors from the computer.
Use a ratchet wrench to remove the retaining bolts that hold the computer in place and lift the computer out of the engine compartment.
Slip the new computer into the engine compartment. Use a ratchet wrench to replace the retaining bolts.
Attach the electrical connectors to the computer. The connectors are color coded to match the colors on the plugs of the computer.
Put the car horn in place, reattach the bolt at the back of the horn with a ratchet wrench, and attach the electrical connector.
Put the splash shield back into position, install the fasteners and use a ratchet wrench to attach the splash shield to the fender.
Put the driver's side wheel back in place and install the lug nuts with a torque wrench, tightening them to 100 ft-lbs.
Support the vehicle with an automotive jack, remove the jack stands and lower the front of the vehicle.
Start the car, which will immediately stall. The "Theft" light will be flashing on the instrument cluster. Leave the key in the "ON" position until the lights stop flashing and turn solid.
Turn the key to the "OFF" position, wait 30 seconds and start the car.
