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 PGM-FI subrelay, and the PCM.
5. Turn the ignition switch OFF.
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. Test the PGM-FI subrelay (E) in the under-hood fuse/relay box.
Is the PGM-FI subrelay OK?
YES - Go to step 8.
NO - Replace the PGM-FI subrelay, then go to step 27.
8. Disconnect the A/F sensor (Sensor 1) 4P connector.
9. At the sensor side, measure resistance between A/F sensor (Sensor 1) 4P connector terminals No. 3 and No. 4.
Is there 2.0 - 2.7 ohms at room temperature?
YES - Go to step 10.
NO - Go to step 25.
10. 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 25.
NO - Go to step 11.
11. Jump the SCS line with the HDS.
12. Disconnect PCM connector C (44P).
13. Connect A/F sensor (Sensor 1) 4P connector terminal No. 4 to body ground with a jumper wire.
14. Check for continuity between PCM connector terminal C9 and body ground.
Is there continuity?
YES - Go to step 15.
NO - Repair open in the wire between the PCM (C9) and the A/F sensor (Sensor 1), then go to step 26.
15. Remove the PGM-FI subrelay (E) from the under-hood fuse/relay box.
16. Connect A/F sensor (Sensor 1) 4P connector terminal No. 3 to body ground with a jumper wire.
17. Check for continuity between PGM-FI subrelay 4P connector terminal No. 2 and body ground.
Is there continuity?
YES - Go to step 18.
NO - Repair open in the wire between the A/F sensor (Sensor 1) and the PGM-FI subrelay, then go to step 26.
18. Disconnect PCM connector A (44P).
19. Check for continuity between PGM-FI subrelay 4P connector terminal No. 3 and PCM connector terminal A21.
Is there continuity?
YES - Go to step 32.
NO - Repair open in the wire between the PCM (A21) and the PGM-FI subrelay, then go to step 26.
20. Remove the PGM-FI subrelay (E) from the under-hood fuse/relay box.
21. Disconnect the A/F sensor (Sensor 1) 4P connector.
22. Disconnect the EVAP canister purge valve 2P 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. 3 and body ground.
Is there continuity?
YES - Repair 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 26.
NO - Replace the under-hood fuse/relay box, then go to step 26.
25. Replace the A/F sensor (Sensor 1).
26. Reconnect all connectors.
27. Turn the ignition switch ON (II).
28. Reset the PCM with the HDS.
29. Do the PCM idle learn procedure.
30. 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 PGM-FI subrelay, and the PCM, 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 Temporary DTCs or DTCs were indicated in step 30, 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 PGM-FI subrelay, and the PCM, 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 PCM if it does not have the latest software, or substitute a known-good PCM.
34. Start the engine, and let it idle.
35. 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 PGM-FI subrelay, and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 34. If the PCM 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 PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other Temporary DTCs or DTCs were indicated in step 35, 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 PGM-FI subrelay, and the PCM. If the PCM was updated, substitute a known-good PCM, then go to step 34. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.