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 P or N) 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 PCM.�
5. Turn the ignition switch to LOCK (0).
6. Check the No. 11 LAF (15 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES -
Go to step 7.
NO -
Go to step 20.
7. Remove the PGM-FI subrelay (A) 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 28.
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 26.
11. At the sensor side, check for continuity between A/F sensor (Sensor 1) 4P connector terminals No. 2 and No. 3, and between terminals No. 2 and No. 4 individually.
Is there continuity?
YES -
Go to step 26.
NO -
Go to step 12.
12. Jump the SCS line with the HDS.
13. Disconnect PCM connector C (44P).
14. Connect A/F sensor (Sensor 1) 4P connector terminal No. 4 to body ground with a jumper wire.
15. Check for continuity between PCM connector terminal C9 and body ground.
Is there continuity?
YES -
Go to step 16.
NO -
Repair an open in the wire between the PCM (C9) and the A/F sensor (Sensor 1), then go to step 27.
16. Remove the PGM-FI subrelay (A) from the under-hood fuse/relay box.
17. Connect A/F sensor (Sensor 1) 4P connector terminal No. 3 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 an open in the wire between the A/F sensor (Sensor 1) and the PGM-FI subrelay, then go to step 27.
19. Disconnect PCM connector A (44P).
20. Check for continuity between PCM connector terminal A21 and PGM-FI subrelay 4P connector terminal No. 3.
Is there continuity?
YES -
Go to step 33.
NO -
Repair an open in the wire between the PCM(A21) and the PGM-FI subrelay, then go to step 27.
21. Remove the PGM-FI subrelay (A) from the under-hood fuse/relay box.
22. Disconnect the A/F sensor (Sensor 1) 4P connector.
23. Disconnect the EVAP canister purge valve 2P connector.
24. Disconnect the EVAP canister vent shut valve 2P connector.
25. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 3 and body ground.
Is there continuity?
YES -
Repair a short in the wire between the PGM-FI subrelay, the EVAP canister purge valve, the EVAP canister vent shut valve, and the A/F sensor(Sensor 1). Also replace the No. 11 LAF (15 A) fuse, then go to step 27.
NO -
Replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal/Installation, then go to step 27.
26. Replace the A/F sensor (Sensor 1) A/F Sensor Replacement.
27. Reconnect all connectors.
28. Turn the ignition switch to ON (II).
29. Reset the PCM with the HDS.
30. Do the PCM idle learn procedure PCM Idle Learn Procedure.
31. 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 PCM, then go to step 1.
NO -
Go to step 32.
32. 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 PCM, then go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.
33. Reconnect all connectors.
34. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM Initial Inspection and Diagnostic Overview.
35. Start the engine, and let it idle.
36. 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 PCM. If the PCM was updated, substitute a known-good PCM Initial Inspection and Diagnostic Overview, then go to step 35. If the PCM was substituted, go to step 1.
NO -
Go to step 37.
37. Monitor the OBD STATUS for DTC P0135 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs were indicated in step 36, 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 PCM. If the PCM was updated, substitute a known-good PCM Initial Inspection and Diagnostic Overview, then go to step 35. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.