Service Engine Soon Indicator

The SERVICE ENGINE SOON warning indicator is controlled by the powertrain control module (PCM) through circuit 419. The PCM turns on the indicator for approximately 3 seconds during engine start-up in order to perform a bulb test. The PCM will illuminate the SERVICE ENGINE SOON warning indicator in order to warn the driver that an engine control malfunction has been detected that may affect engine performance. Refer to Powertrain Control Module (PCM) Description in Computers and Control Systems - 3.5L for more information.