DTC Troubleshooting
DTC P0135: Rear A/F Sensor (Bank 1, Sensor 1) Heater Circuit MalfunctionDTC 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.
- Information marked with an asterisk (*) applies to the front bank (Bank 2).
1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Start the engine.
4. Check for Temporary DTCs or 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 PGM-FI subrelay (LAF), the driver's under-dash fuse/relay box, and the PCM.
5. Turn the ignition switch OFF.
6. Check these fuses:
- No. 19 OPTION 1 (30 A) fuse in the under-hood fuse/relay box.
- No. 4 LAF (A/F SENSOR) (15 A) fuse in the driver's under-dash fuse/relay box.
- No. 23 IGP (7.5 A) fuse in the driver's under-dash fuse/relay box.
Are any of the fuses blown?
YES - Repair short in the wire between the A/F sensors, PGM-FI subrelay (LAF), then replace the blown fuse(s), and go to step 24.
NO - Go to step 7.
7. Disconnect the A/F sensor (Sensor 1) 6P connector.
8. At the sensor side, measure resistance between A/F sensor (Sensor 1) 6P connector terminals No. 1 and No. 2.
Is there 2.5 - 3.2 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 at the A/F sensor (Sensor 1) 6P connector and body ground.
Is there continuity?
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 C (49P).
13. Check for continuity between PCM connector terminal C6 (C8)* and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (C6 (C8)*) and the A/F sensor (Sensor 1), then go to step 23.
NO - Go to step 14.
14. Check for continuity between A/F sensor (Sensor 1) 6P connector terminal No. 2 and PCM connector terminal C6 (C8)*.
Is there continuity?
YES - Go to step 15.
NO - Repair open in the wire between the PCM (C6 (C8)*) and the A/F sensor (Sensor 1), then go to step 23.
15. Remove the PGM-FI subrelay (LAF) (A).
16. Connect A/F sensor (Sensor 1) 6P connector terminal No. 1 to body ground with a jumper wire.
17. Check for continuity between PGM-FI subrelay (LAF) 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 (LAF), then go to step 23.
18. Disconnect PCM connector A (49P).
19. Connect PGM-FI subrelay (LAF) 4P connector terminal No. 3 to body ground with a jumper wire.
20. Check for continuity between PCM connector terminal A40 and body ground.
Is there continuity?
YES - Go to step 21.
NO - Repair open in the wire between the PCM (A21) and the PGM-FI subrelay (LAF), then go to step 23.
21. Test the PGM-FI subrelay (LAF).
Is the PGM-FI subrelay (LAF) OK?
YES - Go to step 29.
NO - Replace the PGM-FI subrelay (LAF), then go to step 23.
22. Replace the A/F sensor (Sensor 1).
23. Reconnect all connectors.
24. Turn the ignition switch ON (II).
25. Reset the PCM with the HDS.
26. Do the PCM idle learn procedure.
27. Check for Temporary DTCs or 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 PGM-FI subrelay (LAF), the driver's 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 Temporary DTCs or DTCs were indicated in step 27, 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 (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, or substitute a known-good PCM.
31. Check for Temporary DTCs or 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 PGM-FI subrelay (LAF), the driver's under-dash fuse/relay box, and the PCM. If the PCM was updated, substitute a known-good PCM, 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. If any other Temporary DTCs or DTCs were indicated in step 31, 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 (LAF), the driver's under-dash fuse/relay box, and the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.