SELF-DIAGNOSTIC SYSTEM
Note. For additional information, see TESTS W/CODES article.
SELF-DIAGNOSTIC SYSTEM (SINGLE LED - 2 MODES)
Note. Switching modes is not possible to when the engine is running. ECM will switch back to MODE I when ignition is turned off.
Self-diagnostic system will operate in one of 2 modes. On Quest,modes are changed by connecting and removing jumper wire between DTC terminals "A" and "B". On all other models, modes are manually changed using screwdriver through access port on ECM. To change mode, turn ignition on but DO NOT start engine. Turn screwdriver fully clockwise. Wait at least 2 seconds, then turn screwdriver fully counterclockwise. Inspection light will begin to flash.
Mode II (Self-Diagnostics)
When mode is accessed, codes stored in ECM memory will be flashed by the CHECK ENGINE light and the Red LED on the side of the ECM (if equipped). Long flashes (.6 second) represent the first digit of the code. Short flashes (.3 second) represent the second digit of the code. For example: 3 long flashes followed by 5 short flashes of the Red LED (or CHECK ENGINE light) would indicate a Code 35.
SELF-DIAGNOSTIC SYSTEM (DUAL LED - 5 MODES)
The self-diagnostic system is capable of detecting ECCS malfunctions and storing current and intermittent trouble codes. All codes are available for interpretation unless codes have been cleared or ignition has been cycled on-off 50 times since the malfunction last occurred.
Self-diagnostic system will be operated in one of 5 modes. Modes are manually changed using screwdriver through access port on ECM. To enter or change mode, turn screwdriver fully clockwise. Inspection lights will begin to flash. When desired mode has been entered, turn screwdriver fully counterclockwise. Red LED and Green LED perform different functions in different modes.