Description of On-Board Diagnostics

The ECU will substitute the input signals for the air flow meter, throttle sensor and water temperature sensor if the circuits fail. This will allow the vehicle to driven until repairs can be made.
NOTE: The engine will operate at reduced capacity.

Air Flow Meter Malfunction:

AIR FLOW METER MALFUNCTION
If the ECU senses that the air flow meter output voltage is out of the normal range it will substitute the throttle sensor signal for the correct signal. Engine rpm will be limited to 2400 in order to inform the driver that the ECU is in the "Fail-Safe Mode". Refer to the figure for operating conditions.

Fig. 103 Water Temperature Sensor Malfunction:

WATER TEMPERATURE SENSOR MALFUNCTION
When the ECU senses that the engine temperature output voltage is out of the normal range, it will substitute voltage at preset values. Refer to the figure for operating conditions.

Fig. 104 Throttle Sensor Malfunction:

THROTTLE SENSOR MALFUNCTION
When the ECU senses that the throttle sensor is out of range it will substitute the idle switch signal. Refer to the figure for operating conditions.