Diagnostic Procedure

DIAGNOSTIC PROCEDURE FOR DTC 25 AND 26




1. CHECK VOLTAGE OF TERMINAL VF1.
- If voltage continues at 0.0 volts proceed to step 2.
- If voltage continues at 5.0 volts proceed to step 7.
2. CHECK VOLTAGE OF TERMINAL OX1.
- If OK proceed to step 7.
- If not OK proceed to step 3.
3. CHECK FOR OPEN AND SHORT IN HARNESS AND CONNECTOR.
- If OK proceed to step 4.
- If not OK repair or replace harness or connector.
4. CHECK EACH ITEM FOUND TO BE A POSSIBLE CAUSE OF PROBLEM.
- If OK proceed to step 5.
- If not OK repair or replace faulty item.
5. CHECK COMPRESSION.
- If OK proceed to step 6.
- If not OK repair engine.
6. DOES MALFUNCTION DISAPPEAR WHEN A GOOD OXYGEN SENSOR IS INSTALLED ?
- If YES replace oxygen sensor.
- If NO check and replace ECM.
7. CHECK EACH ITEM FOUND TO BE A POSSIBLE CAUSE OF PROBLEM.
- If OK proceed to step 8.
- If not OK repair or replace faulty item.
8. CHECK COMPRESSION.
- If OK proceed to step 9.
- If not OK repair engine.
9. DOES MALFUNCTION DISAPPEAR WHEN A GOOD OXYGEN SENSOR IS INSTALLED?
- If YES replace oxygen sensor.
- If NO check and replace ECM.