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 (A/T in P or N, M/T 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 A/F sensor relay, and the ECM/PCM.
5. Turn the ignition switch to LOCK (0).
6. Check the No. 26 LAF (A/F SENSOR) (10A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES - Go to step 7.
NO - Go to step 20.
7. Open the fuse access panel (A), then remove the A/F sensor relay (B) from the under-dash fuse/relay box.
8. Test the A/F sensor relay. Testing and Inspection
Is the A/F sensor relay OK?
YES - Go to step 9.
NO - Replace the A/F sensor relay, 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 1.9-2.7 Ohms at room temperature?
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 ECM/PCM connector C (49P).
14. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 3 and ECM/PCM connector terminal C9.
Is there continuity?
YES - Go to step 15.
NO - Repair open in the wire between the ECM/PCM (C9) and the A/F sensor (Sensor 1), then go to step 24.
15. Connect A/F sensor (Sensor 1) 4P connector terminal No. 4 to body ground with a jumper wire.
16. Check for continuity between A/F sensor relay 4P connector terminal No. 1 and body ground.
Is there continuity?
YES - Go to step 17.
NO - Repair open in the wire between the A/F sensor (Sensor 1) and the A/F sensor relay, then go to step 24.
17. Disconnect ECM/PCM connector A (49P).
18. Connect ECM/PCM connector terminal A22 to body ground with a jumper wire.
19. Check for continuity between A/F sensor relay 4P connector terminal No. 3 and body ground.
Is there continuity?
YES - Go to step 30.
NO - Repair open in the wire between the ECM/PCM (A22) and the A/F sensor relay, then go to step 24.
20. Open the fuse access panel (A), then remove the A/F sensor relay (B) from the under-dash fuse/relay box.
21. Disconnect the A/F sensor (Sensor 1) 4P connector.
22. 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 A/F sensor relay and the A/F sensor (Sensor 1). Also replace the No. 26 LAF (A/F SENSOR) (10 A) fuse, then go to step 24.
NO - Replace the under-dash fuse/relay box, then go to step 24.
23. Replace the A/F sensor (Sensor 1). A/F Sensor Replacement
24. Reconnect all connectors.
25. Turn the ignition switch to ON (II).
26. Reset the ECM/PCM with the HDS.
27. Do the ECM/PCM idle learn procedure. ECM/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, and the ECM/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 screen indicate PASSED?
YES - Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 28, 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 A/F sensor relay, and the ECM/PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 27.
30. Reconnect all connectors.
31. Update the ECM/PCM if it does not have the latest software, ECM/PCM Update or substitute a known-good ECM/PCM. Initial Inspection and Diagnostic Overview
32. Start the engine.
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, and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then go to step 33. If the ECM/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 screen indicate PASSED?
YES - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. Service and Repair If any other Pending or Confirmed DTCs were indicated in step 33, 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 A/F sensor relay, and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then go to step 32. If the ECM/PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.