DTC Troubleshooting

DTC Troubleshooting: P0135, P0155

DTC P0135: Rear A/F Sensor (Bank 1, Sensor 1) Heater Circuit Malfunction

DTC P0155: Front A/F Sensor (Bank 2, Sensor 1) Heater Circuit Malfunction

NOTE:

- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Reading and Clearing Diagnostic Trouble Codes

- Information marked with an asterisk (*) applies to the front bank (Bank 2).

1. Turn the ignition switch to ON (II).

2. Clear the DTC with the HDS.

3. Start the engine.

4. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0135 and/or P0155* 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. 4 A/F SENSOR (15 A) fuse in the driver's under-dash fuse/relay box.

Is the fuse OK?
YES - Go to step 7.

NO - Repair short in the wire between the front A/F sensor, the rear A/F sensor, the front secondary HO2S, the rear secondary HO2S, the EVAP canister vent shut valve, the A/F sensor relay, and the fuse, then replace the blown fuse, and go to step 24.


7. Disconnect the A/F sensor (Sensor 1) 6P connector.

8. At the sensor side, measure the resistance between A/F sensor (Sensor 1) 6P connector terminals No. 1 and No. 2.

Is there 2.5-2.9 Ohms at room temperature?
YES - Go to step 9.

NO - Go to step 22.






9. At the sensor side, check for continuity between each terminal of the A/F sensor (Sensor 1) 6P connector and body ground.

Is there continuity to ground at any of the terminals?
YES - Go to step 22.

NO - Go to step 10.






10. At the sensor side, check for continuity between A/F sensor (Sensor 1) 6P connector terminals No. 1 and No. 4, No. 1 and No. 5, No. 1, and No. 6 individually.

Is there continuity?
YES - Go to step 22.

NO - Go to step 11.






11. Jump the SCS line with the HDS.

12. Disconnect PCM connector A (31P).

13. Check for continuity between PCM connector terminal A7 (A6)* and body ground.

Is there continuity?
YES - Repair short in the wire between the PCM (A7 (A6)*) and the A/F sensor (Sensor 1), then go to step 23.

NO - Go to step 14.






14. Connect A/F sensor (Sensor 1) 6P connector terminal No. 2 to body ground with a jumper wire.






15. Check for continuity between PCM connector terminal A7 (A6)* and body ground.

Is there continuity?
YES - Go to step 16.

NO - Repair open in the wire between the PCM (A7 (A6)*) and the A/F sensor (Sensor 1), then go to step 23.






16. Remove the A/F sensor relay (LAF) (A) from the driver's under-dash fuse/relay box.






17. Connect A/F sensor (Sensor 1) 6P connector terminal No. 1 to body ground with a jumper wire.






18. Check for continuity between A/F sensor relay (LAF) 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 (LAF), then go to step 23.






19. Disconnect PCM connector E (31P).

20. Check for continuity between PCM connector terminal E4 and A/F sensor relay (LAF) 4P connector terminal No. 3.

Is there continuity?
YES - Go to step 21.

NO - Repair open in the wire between the PCM (E4) and the A/F sensor relay (LAF), then go to step 23.






21. Test the A/F sensor relay (LAF). Power Relay Test

Is the A/F sensor relay OK?
YES - Go to step 29.

NO - Replace the A/F sensor relay (LAF), then go to step 23.


22. Replace the A/F sensor (Sensor 1). A/F Sensor Replacement

23. Reconnect all connectors.

24. Turn the ignition switch to ON (II).

25. Reset the PCM with the HDS.

26. Do the PCM idle learn procedure. PCM Idle Learn Procedure

27. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0135 and/or P0155* indicated?
YES - Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the A/F sensor relay (LAF), the under-dash fuse/relay box, and the PCM, then go to step 1.

NO - Go to step 28.


28. Monitor the OBD STATUS for DTC P0135 and/or P0155* 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 27, 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 (LAF), the driver's under-dash fuse/relay box, and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.


29. Reconnect all connectors.

30. Update the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM. Reading and Clearing Diagnostic Trouble Codes

31. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0135 and/or P0155* indicated?
YES - Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the A/F sensor relay (LAF), the driver's under-dash fuse/relay box, and the PCM. If the PCM was updated, substitute a known-good PCM, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1.

NO - Go to step 32.


32. Monitor the OBD STATUS for DTC P0135 and/or P0155* 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 31, 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 (LAF), the driver's under-dash fuse/relay box, and the PCM. If the PCM was updated, substitute a known-good PCM, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.