DTC Troubleshooting
DTC Troubleshooting: P0135
DTC P0135:
A/F Sensor (Sensor 1) Heater Circuit Malfunction
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information Initial Inspection and Diagnostic Overview.
1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.
4. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0135 indicated?
YES -
Go to step 5.
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM.�
5. Turn the ignition switch to LOCK (0).
6. Check the No. 11 FI SUB (15 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES -
Go to step 7.
NO -
Go to step 21.
7. Remove the PGM-FI subrelay (E) from the under-hood fuse/relay box.
8. Test the PGM-FI subrelay Testing and Inspection.
Is the PGM-FI subrelay OK?
YES -
Go to step 9.
NO -
Replace the PGM-FI subrelay, then go to step 26.
9. Disconnect the A/F sensor (Sensor 1) 4P connector.
10. At the sensor side, measure the resistance between A/F sensor (Sensor 1) 4P connector terminals No. 3 and No. 4.
Is there 2.0-2.7 Ohms at room temperature?
YES -
Go to step 11.
NO -
Go to step 25.
11. At the sensor side, check for continuity between A/F sensor (Sensor 1) 4P connector terminals No. 1 and No. 3, and between terminals No. 1 and No. 4 individually.
Is there continuity?
YES -
Go to step 25.
NO -
Go to step 12.
12. Jump the SCS line with the HDS.
13. Disconnect ECM connector C (44P).
14. Check for continuity between ECM connector terminal C9 and body ground.
Is there continuity?
YES -
Repair short in the wire between the ECM (C9) and the A/F sensor (Sensor 1), then go to step 26.
NO -
Go to step 15.
15. Connect A/F sensor (Sensor 1) 4P connector terminal No. 3 to body ground with a jumper wire.
16. Check for continuity between ECM connector terminal C9 and body ground.
Is there continuity?
YES -
Go to step 17.
NO -
Repair open in the wire between the ECM (C9) and the A/F sensor (Sensor 1), then go to step 26.
17. Connect A/F sensor (Sensor 1) 4P connector terminal No. 4 to body ground with a jumper wire.
18. Check for continuity between PGM-FI subrelay 4P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Go to step 19.
NO -
Repair open in the wire between the A/F sensor (Sensor 1) and the PGM-FI subrelay, then go to step 26.
19. Disconnect ECM connector A (44P).
20. Check for continuity between PGM-FI subrelay 4P connector terminal No. 3 and ECM connector terminal A21.
Is there continuity?
YES -
Go to step 32.
NO -
Repair open in the wire between the ECM (A21) and the PGM-FI subrelay, then go to step 26.
21. Remove the PGM-FI subrelay (E) from the under-hood fuse/relay box.
22. Disconnect the A/F sensor (Sensor 1) 4P connector.
23. Disconnect the EVAP canister vent shut valve 2P connector.
24. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 4 and body ground.
Is there continuity?
YES -
Repair short in the wire between the PGM-FI subrelay, the EVAP canister vent shut valve, and the A/F sensor (Sensor 1). Also replace the No. 11 FI SUB (15 A) fuse, then go to step 26.
NO -
Replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation, then go to step 26.
25. Replace the A/F sensor (Sensor 1) A/F Sensor Replacement.
26. Reconnect all connectors.
27. Turn the ignition switch to ON (II).
28. Reset the ECM with the HDS.
29. Do the ECM idle learn procedure ECM/PCM Idle Learn Procedure.
30. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0135 indicated?
YES -
Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM, then go to step 1.
NO -
Go to step 31.
31. Monitor the OBD STATUS for DTC P0135 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 30, go to the indicated DTC's troubleshooting.�
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM, then go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.
32. Reconnect all connectors.
33. Update the ECM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM.
34. Start the engine, and let it idle.
35. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0135 indicated?
YES -
Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM. If the ECM was updated, substitute a known-good ECM, then go to step 34. If the ECM was substituted, go to step 1.
NO -
Go to step 36.
36. Monitor the OBD STATUS for DTC P0135 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM Service and Repair. If any other Pending or Confirmed DTCs were indicated in step 35, go to the indicated DTC's troubleshooting.�
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the PGM-FI subrelay, and the ECM. If the ECM was updated, substitute a known-good ECM, then go to step 34. If the ECM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.