DTC Troubleshooting: P0135 (41)

DTC P0135:  A/F sensor (Sensor 1) Heater Circuit Malfunction


1.Turn the ignition switch ON (II).

2.Do the DTC CLEAR in the CLEAR MENU with the Honda PGM Tester or the HDS.

3.Start the engine.

4.Check for Temporary DTCs or DTCs in the DTCs MENU with the Honda PGM Tester or the HDS.

Is DTC P0135 indicated?


YES - Go to 5.


NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the  A/F sensor (Sensor 1) and the  ECM/PCM.n


5.Turn the ignition switch OFF.

6.Check the following fuses:
  • No. 19 OPTION (40A) fuse in under-hood fuse/ relay box.
  • No. 4 A/F SENSOR (15A) fuse in under-dash fuse/relay box.
  • No. 23 IGP (7.5A) fuse in under-dash fuse/relay box.

Are any of the fuses blown?


YES - Repair short in the wire between the A/F sensor relay and the fuses, then go to 23.


NO - Go to 7.


7.Disconnect the A/F sensor (Sensor 1) 4P connector.

8.At the A/F sensor (Sensor 1) side, measure resistance between A/F sensor (Sensor 1) 4P connector terminals No. 3 and No. 4.

Is there 2.1-2.9 W at room temperature?


YES - Go to 9.


NO - Go to 22.


9.Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 1 and A/F sensor (Sensor 1) 4P connector terminals No. 3 and No. 4 individually.

Is there continuity?


YES - Go to 22.


NO - Go to 10..


10.Jump the SCS line with the Honda PGM Tester or the HDS.

11.Disconnect ECM/PCM connector A (31P).

12.Check for continuity between ECM/PCM connector terminals 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 23.


NO - Go to 13.

13.Connect the A/F sensor (Sensor 1) 4P connector terminal No. 3 to body ground with a jumper wire.

14.Check for continuity between ECM/PCM connector terminal A10 and body ground.

Is there continuity?


YES - Repair open in the wire between the ECM/PCM (A10) and the A/F sensor (Sensor 1), then go to 23.


NO - Go to 15.

15.Connect the A/F sensor (Sensor 1) 4P connector terminal No. 4 to body ground with a jumper wire.

16.Check for continuity between A/F sensor relay terminal No. 2 and body ground.

Is there continuity?


YES - Go to 17.


NO - Repair open in the wire between the A/F sensor (Sensor 1) and the A/F sensor relay, then go to 23.

17.Remove the A/F sensor relay (A).

18.Disconnect ECM/PCM connector E (31P).

19.Check for continuity between ECM/PCM connector terminals E8 and body ground.

Is there continuity?


YES - Repair short in the wire between the ECM/PCM (E8) and the A/F sensor relay, then go to 23.


NO - Go to 20.

20.Check for continuity between ECM/PCM connector terminal E8 and the A/F sensor relay terminal No. 4.

Is there continuity?


YES - Go to 21.


NO - Repair open in the wire between the ECM/PCM (E8) and the A/F sensor relay, then go to 23.


21.Check the A/F sensor relay.

Is the A/F sensor relay OK?


YES - Go to 28.


NO - Replace the A/F sensor relay, then go to 23.

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

23.Turn the ignition switch ON (II).

24.Do the ECM/PCM RESET in the CLEAR MENU with the Honda PGM Tester or the HDS.

25.Do the ECM/PCM idle learn procedure.

26.Check for Temporary DTCs or DTCs in the DTCs MENU with the Honda PGM Tester or the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC P0135 is indicated, check for poor connections or loose terminals at the  A/F sensor (Sensor 1) and the  ECM/PCM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC troubleshooting.


NO - Go to 27.


27.Monitor the OBD STATUS for DTC P0135 in the DTCs MENU with the Honda PGM Tester or the HDS.

Is it PASSED?


YES - Troubleshooting is complete.n


NO - If it is FAILED, check for poor connections or loose terminals at the  A/F sensor (Sensor 1) and the  ECM/PCM, then go to 1. If it is NOT COMPLETED, go to 25 and recheck.

28.Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.

29.Check for Temporary DTCs or DTCs in the DTCs MENU with the Honda PGM Tester or the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC P0135 is indicated, check for poor connections or loose terminals at the  A/F sensor (Sensor 1), and the A/F sensor relay and the  ECM/PCM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC troubleshooting.


NO - If the  ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM.