P0056

DTC P0056: Front Secondary HO2S (Bank 2, Sensor 2) Heater Circuit Malfunction

NOTE: 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 P0036 and/or P0056* indicated?

YES - Go to step 5.

NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the PCM.

5. Turn the ignition switch OFF.
6. Disconnect the secondary HO2S (Sensor 2) 4P connector.




7. At the secondary HO2S (Sensor 2) side, measure resistance between secondary HO2S (Sensor 2) 4P connector terminals No.3 and No.4.

Is there 5.4 - 6.6 Ohms, at room temperature?

YES - Go to step 8.

NO - Go to step 14.




8. Check for continuity between body ground and secondary HO2S (Sensor 2) 4P connector terminals No.3 and No.4 individually.

Is there continuity?

YES - Go to step 14.

NO - Go to step 9.

9. Jump the SCS line with the HDS.
10. Disconnect PCM connector A (73P).




11. Check for continuity between PCM connector terminals A59 (A60)* and body ground.

Is there continuity?

YES - Repair short in the wire between the PCM (A59 (A60)*) and the secondary HO2S (Sensor 2), then go to step 15.

NO - Go to step 12.




12. Connect secondary HO2S (Sensor 2) 4P connector terminal No.3 to body ground with a jumper wire.




13. Check for continuity between PCM connector terminal A59 (A60)* and body ground.

Is there continuity?

YES - Go to step 20.

NO - Repair open in the wire between the PCM (A59 (A60)*) and the secondary HO2S (Sensor 2), then go to step 15.

14. Replace the secondary HO2S (Sensor 2).
15. Reconnect all connectors.
16. Turn the ignition switch ON (II).
17. Reset the PCM with the HDS.
18. Do the PCM idle learn procedure.
19. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P0036 and/or P0056* is indicated, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - Go to step 20.

20. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
21. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P0036 and/or P0056* is indicated, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

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