Diagnostic Procedure

DIAGNOSTIC PROCEDURE






NOTE: When other codes are output in addition to 27 at the same time, check the circuits for other codes first.

1. Check voltage of terminal HT3.
- If OK proceed to step 4.
- If not OK proceed to step 2.
2. Check resistance of Sub Heated Oxygen Sensor heater.
- If OK proceed to step 3.
- If not OK replace sub heated oxygen sensor.
3. Check for open and short in harness and connector between EFI Main Relay and Engine Control Module.
- If OK check and replace Engine Control Module.
- If not OK repair or replace harness or connector.
4. Check operation of Sub Heated Oxygen Sensor heater.
- If OK replace Sub Heated Oxygen Sensor.
- If not OK check and replace Engine Control Module.