Self-Diagnostic Feature: Notes

PCM has a self-diagnostic feature which detects malfunctions in emission-related components and stores Diagnostic Trouble Codes (DTCs). PCM provides a substitute value if a failure occurs in engine (coolant) temperature sensor, intake air temperature sensor, airflow meter or exhaust gas oxygen sensor. These substitute values are canceled when normal engine operation is resumed. To aid in trouble shooting, stored fault codes and sensor values can be monitored via PCM and actuated components.

Vehicles are equipped with an OBD-II self-diagnostic system which can utilize a generic scan tool connected to in-vehicle Data Link Connector (DLC). In addition, vehicles are also equipped with a BMW self-diagnostic system which accesses DTCs using special BMW hardware and software connected to underhood BMW engine diagnostic connector socket. See SELF-DIAGNOSTICS article.