How do you replace PCM on 1998 Cadillac Catera?

To replace the PCM (Powertrain Control Module) on a 1998 Cadillac Catera, first disconnect the battery to ensure safety. Then, locate the PCM, which is usually found in the engine compartment or under the dashboard. Remove any connectors and screws holding it in place, then take out the old PCM. Install the new PCM by reversing the removal process, reconnecting the battery, and ensuring the system is properly calibrated if necessary.