DTC Troubleshooting
DTC P0135: A/F Sensor (Sensor 1) Heater Circuit MalfunctionNOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
4. Check for Temporary DTCs or 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 OFF.
6. Check these fuses:
- No. 23 LAF (10 A) fuse in the under-dash fuse/relay box.
- No. 31 LAF (7.5 A) fuse in the under-dash fuse/relay box.
Are either of the above fuses blown?
YES - Go to step 24.
NO - Go to step 7.
7. Remove the A/F sensor relay (A).
8. Check the A/F sensor relay.
Is the A/F sensor relay OK?
YES - Go to step 9.
NO - Replace the A/F sensor relay, then go to step 33.
9. Disconnect the A/F sensor (Sensor 1) 4P connector.
10. At the sensor side, measure resistance between A/F sensor (Sensor 1) 4P connector terminals No. 3 and No. 4.
Is there 2.0 - 2.6 ohms at room temperature?
YES - Go to step 11.
NO - Go to step 32.
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 32.
NO - Go to step 12.
12. Jump the SCS line with the HDS.
13. Disconnect ECM/PCM connector A (31P).
14. Check for continuity between ECM/PCM connector terminal A10 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (A10) and the A/F sensor (Sensor 1), then go to step 33.
NO - Go to step 15.
15. Connect A/F sensor (Sensor 1) 4P connector terminal No. 4 to body ground with a jumper wire.
16. Check for continuity between ECM/PCM connector terminal A10 and body ground.
Is there continuity?
YES - Go to step 17.
NO - Repair open in the wire between the ECM/PCM (A10) and the A/F sensor (Sensor 1), then go to step 33.
17. Connect A/F sensor (Sensor 1) 4P connector terminal No. 3 to body ground with a jumper wire.
18. Check for continuity between A/F sensor relay 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 A/F sensor relay, then go to step 33.
19. Disconnect ECM/PCM connector E (31P).
20. Check for continuity between ECM/PCM connector terminal E8 and A/F sensor relay 4P connector terminal No. 3.
Is there continuity?
YES - Go to step 21.
NO - Repair open in the wire between the ECM/PCM (E8) and the A/F sensor relay, then go to step 33.
21. Measure voltage between A/F sensor relay 4P connector terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 22.
NO - Repair open in the wire between the A/F sensor relay and the No. 23 LAF (10 A) fuse or the No. 9 SMALL LIGHT (30 A) fuse, then go to step 33.
22. Turn the ignition switch ON (II).
23. Measure voltage between A/F sensor relay 4P connector terminal No. 4 and body ground.
Is there battery voltage?
YES - Go to step 39.
NO - Repair open in the wire between the A/F sensor relay and the No. 31 LAF (7.5 A) fuse, then go to step 33.
24. Remove the A/F sensor relay (A).
25. Disconnect the A/F sensor (Sensor 1) 4P connector.
26. Disconnect the EVAP canister vent shut valve 2P connector.
27. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 3 and body ground.
Is there continuity?
YES - Repair short in the wire between the A/F sensor (Sensor 1), the A/F sensor relay, and the EVAP canister vent shut valve. Also replace the No. 23 LAF (10 A) fuse, then go to step 33.
NO - Go to step 28.
28. Disconnect the 14P connector from the under-dash fuse/relay box.
29. Check for continuity between A/F sensor relay 4P connector terminal No. 1 and body ground.
Is there continuity?
YES - Repair short in the wire between the A/F sensor relay and the under-dash fuse/relay box. Also replace the No. 23 LAF (10 A) fuse, then go to step 33.
NO - Go to step 30.
30. Remove the No. 31 LAF (7.5 A) fuse from under-dash fuse/relay box.
31. Check for continuity between A/F sensor relay 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 under-dash fuse/relay box. Also replace the No. 31 LAF (7.5 A) fuse, then go to step 33.
NO - Replace the dashboard wire harness, then go to step 33.
32. Replace the A/F sensor (Sensor 1).
33. Reconnect all connectors.
34. Turn the ignition switch ON (II).
35. Reset the ECM/PCM with the HDS.
36. Do the ECM/PCM idle learn procedure.
37. Check for Temporary DTCs or 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 38.
38. 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. Temporary DTCs or DTCs were indicated in step 37, go to the indicated DTCs 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 36.
39. Turn the ignition switch OFF.
40. Reconnect all connectors.
41. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
42. Start the engine.
43. Check for Temporary DTCs or 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, then go to step 42. If the ECM/PCM was substituted, go to step 1.
NO - Go to step 43.
44. 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. If any other Temporary DTCs or DTCs were indicated in step 43, go to the indicated DTCs 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, then go to step 40. If the ECM/PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, let the engine idle until a result comes on.