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 A/F sensor relay (LAF), and the PCM.�
5. Turn the ignition switch to LOCK (0).
6. Check the No. 11 +B LAF (A/F SENSOR) (15 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES -
Go to step 7.
NO -
Go to step 19.
7. Remove the A/F sensor relay (LAF) (A) from the under-hood fuse/relay box.
8. Test the A/F sensor relay (LAF). Testing and Inspection.
Is the relay OK?
YES -
Go to step 9.
NO -
Replace the A/F sensor relay (LAF), then go to step 24.
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 (65-70°F, 18- 21°C)?
YES -
Go to step 11.
NO -
Go to step 23.
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 23.
NO -
Go to step 12.
12. Jump the SCS line with the HDS.
13. Disconnect PCM connector C (49P).
14. Check for continuity between PCM connector terminal C9 and body ground.
Is there continuity?
YES -
Repair a short in the wire between the PCM (C9) and the A/F sensor (Sensor 1), then go to step 24.
NO -
Go to step 15.
15. Check for continuity between PCM connector terminal C9 and A/F sensor (Sensor 1) 4P connector terminal No. 4.
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 24.
16. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 3 and A/F sensor relay (LAF) 4P connector terminal No. 2.
Is there continuity?
YES -
Go to step 17.
NO -
Repair an open in the wire between the A/F sensor (Sensor 1) and the A/F sensor relay (LAF), then go to step 24.
17. Disconnect PCM connector A (49P).
18. Check for continuity between PCM connector terminal A22 and A/F sensor relay (LAF) 4P connector terminal No. 3.
Is there continuity?
YES -
Go to step 30.
NO -
Repair an open in the wire between the PCM (A22) and the A/F sensor relay (LAF), then go to step 24.
19. Remove the A/F sensor relay (A) from the under-hood fuse/relay box.
20. Disconnect the A/F sensor (Sensor 1) 4P connector.
21. Disconnect the EVAP canister vent shut valve 2P connector.
22. 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 A/F sensor relay (LAF), the A/F sensor (Sensor 1), and the EVAP canister vent shut valve. Also replace the No. 11 +B LAF (A/F SENSOR) (15 A) fuse, then go to step 24.
NO -
Check the under-hood fuse/relay box, and replace it if needed Under-Hood Fuse/Relay Box Removal/Installation, then go to step 24.
23. Replace the A/F sensor (Sensor 1).
24. Reconnect all connectors.
25. Turn the ignition switch to ON (II).
26. Reset the PCM with the HDS.
27. Do the PCM idle learn procedure. PCM Idle Learn Procedure
28. 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 A/F sensor relay (LAF), and the PCM, then go to step 1.
NO -
Go to step 29.
29. Monitor the OBD STATUS for DTC P0135 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 28 P0135, go to the indicated DTC's troubleshooting.�
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the A/F sensor relay (LAF), and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.
30. Reconnect all connectors.
31. Update the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM. Initial Inspection and Diagnostic Overview
32. Start the engine, and let it idle.
33. 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 A/F sensor relay (LAF), and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 32. If the PCM was substituted, go to step 1.
NO -
Go to step 34.
34. Monitor the OBD STATUS for DTC P0135 in the DTCs MENU with the HDS.
Does the HDS 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 33 P0135, go to the indicated DTC's troubleshooting.�
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the A/F sensor relay (LAF), and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 32. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.