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 Initial Inspection and Diagnostic Overview.
- 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, the under-dash fuse/relay box, and the PCM.�
5. Turn the ignition switch to LOCK (0).
6. Check these fuses:
- No. 17 OP1 (40 A) fuse in the under-hood fuse/relay box
- No. 4 LAF (A/F SENSOR) (15 A) fuse in the under-dash fuse/relay box
- No. 23 IGP (7.5 A) fuse in the under-dash fuse/relay box
Are any of the above fuses blown?
YES -
Repair a short in the wires between the A/F sensors and the A/F sensor relay, then replace the blown fuse(s), and go to step 25.
NO -
Go to step 7.
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 2.5-3.2 Ohms at room temperature (65-70°F, 18-21°C)?
YES -
Go to step 9.
NO -
Go to step 23.
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 23.
NO -
Go to step 10.
10. At the sensor side, check for continuity between A/F sensor (Sensor 1) 6P connector terminal No. 1 and each of the other terminals in the connector individually.
Is there continuity?
YES -
Go to step 23.
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 a short in the wire between the PCM(C6 (C8)*) and the A/F sensor (Sensor 1), then go to step 24.
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 C6 (C8)*and body ground.
Is there continuity?
YES -
Go to step 16.
NO -
Repair an open in the wire between the PCM(C6 (C8)*) and the A/F sensor (Sensor 1), then go to step 24.
16. Remove the A/F sensor relay (A) from the 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 4P connector terminal No. 2 and body ground.
Is there continuity?
YES -
Go to step 19.
NO -
Repair an open in the wire between the A/F sensor (Sensor 1) and the A/F sensor relay, then go to step 24.
19. Disconnect PCM connector A (49P).
20. Connect A/F sensor relay 4P connector terminal No. 3 to body ground with a jumper wire.
21. Check for continuity between PCM connector terminal A40 and body ground.
Is there continuity?
YES -
Go to step 22.
NO -
Repair an open in the wire between the PCM(A40) and the A/F sensor relay, then go to step 24.
22. Test the A/F sensor relay Power Relay Test.
Is the A/F sensor relay OK?
YES -
Go to step 30.
NO -
Replace the A/F sensor relay, 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 PCM with the HDS.
27. Do the PCM idle learn procedure PCM Idle Learn Procedure.
28. 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, the under-dash fuse/relay box, and the PCM, then go to step 1.
NO -
Go to step 29.
29. Monitor the OBD STATUS for DTC P0135 and/or P0155* in the DTCs MENU with the HDS.
Does the HDS 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 HDS indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the A/F sensor relay, the under-dash fuse/relay box, and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.
30. Reconnect all connectors.
31. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
32. 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, the 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 33.
33. Monitor the OBD STATUS for DTC P0135 and/or P0155* in the DTCs MENU with the HDS.
Does the HDS 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 32, go to the indicated DTC's troubleshooting.�
NO -
If the HDS indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the A/F sensor relay, the 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 HDS indicates NOT COMPLETED, keep idling until a result comes on.