Self-Diagnosis Function

The powertrain control module (PCM) diagnoses any troubles which may occur in the engine control system when the ignition switch is in the ON position with the engine running. The PCM indicates a malfunction by illuminating the malfunction indicator lamp (MIL) when a fault occurs in any of the following systems:

• The heated oxygen sensor 1 (HO2S 1)
• The heated oxygen sensor 2 (HO2S 2)
• The engine coolant temperature (ECT) sensor
• The throttle position (TP) sensor (including the CTP switch)
• The vehicle speed sensor (VSS)
• The intake air temperature (IAT) sensor
• The mass air flow (MAF) sensor
• The camshaft position (CMP) sensor
• The crankshaft position (CKP) sensor
• The knock sensor (KS) system
• The evaporative emission (EVAP) control system
• The idle air control (IAC) system
• The CMP actuator solenoid system
• The misfire detection
• The fuel-trim
• The catalyst monitor
• The central processing unit (CPU) of the PCM

When the PCM detects a malfunction in one of the above areas, the PCM will illuminate or flash the MIL in order to notify the driver of the occurrence of a fault.