Locate the ECM. In most Lesabres, it's located on the passenger side of the engine compartment, mounted to the inner fender.
Disconnect the battery. This will erase the ECM's memory.
Wait at least 30 seconds before reconnecting the battery. This gives the ECM time to reset.
After reconnecting the battery, turn on the ignition switch but don't start the engine. This allows the ECM to initialize.
Start the engine and let it run for a few minutes. This allows the ECM to learn the engine's characteristics and adjust its settings accordingly.
