Using Malfunction Indicator Light
The Malfunction Indicator Light (MIL) is located on the instrument panel. The MIL will illuminate when the ignition switch is turned to ON position without the engine running. This is a bulb check (diagnostic mode 1). See Fig 1. If the MIL does not illuminate, see WARNING LIGHTS in appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. When the engine is started, the MIL should go out. If the MIL remains illuminated, the on-board diagnostic system has detected an engine system malfunction. When there is an open circuit in the MIL circuit, the ECM cannot warn the driver by illuminating the MIL when there is a engine control system malfunction. When electrical controlled throttle and part of ECM related diagnosis are continuously detected as NG for 5 trips, ECM warns the driver that engine control system malfunction exists and MIL circuit is open by means of operating fail-safe function. The fail-safe function also operates when diagnosis except MIL circuit are detected and demands the driver to repair the malfunction. When the engine is operating in fail-safe mode, the engine speed will not exceed 2500 RPM due to the fuel cut.
If ECM is in diagnostic test mode II, MIL may flash when engine is running. In this case, check ECM diagnostic test mode. See SWITCHING DIAGNOSTIC TEST MODE . The following emission-related diagnostic information is cleared when ECM memory is erased:
- Diagnostic Trouble Codes (DTC).
- 1st trip DTCs.
- Freeze frame data.
- 1st trip freeze frame data.
- System Readiness Test (SRT) codes.
- Test values.
- Others.