P0157

DTC P0157: Front Secondary HO2S (Bank 2, Sensor 2) Circuit Low Voltage

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. Hold the engine speed at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on, then let it idle.
4. Check the AF FB AVE in the DATA LIST with the HDS.

Is the value 1.00 or more?

YES - Go to step 5.

NO - Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the PCM, then go to step 1.

5. Check the HO2S S2 in the DATA LIST with the HDS.

Is the voltage 0.29 V or less?

YES - Go to step 6.

NO - Go to step 10.

6. Turn the ignition switch OFF.
7. Disconnect the secondary HO2S (Sensor 2) 4P connector.
8. Turn the ignition switch ON (II).
9. Check the HO2S S2 in the DATA LIST with the HDS.

Is voltage 0.29 V or less?

YES - Go to step 12.

NO - Go to step 16.

10. Test-drive under the following conditions.
- Engine coolant temperature more than 158 °F (70 °C)
- A/T in D position
- Engine speed at 2,000 - 3,000 rpm
- Drive about 10 minutes, then decelerate (with the throttle fully closed) for 5 seconds

11. Monitor the OBD STATUS for DTC P0137 or P0157* in the DTCs MENU with the HDS.

Does the screen indicate FAILED?

YES - Go to step 16.

NO - If the screen indicates PASSED, intermittent failure, system is OK at this time. If the screen indicates EXECUTING, keep the driving condition continually until a result comes on. If the screen indicates OUT OF CONDITION, go to step 10 and recheck.

12. Turn the ignition switch OFF.
13. Jump the SCS line with the HDS.
14. Disconnect PCM connector A (73P).




15. Check for continuity between Secondary HO2S (Sensor 2) 4P connector terminal No.1 and body ground.

Is there continuity?

YES - Repair short in the wire between the PCM (A21 (A22)*) and the secondary HO2S (Sensor 2), then go to step 19.

NO - Go to step 26.

16. Turn the ignition switch OFF.
17. Replace the secondary HO2S (Sensor 2), then go to step 19.
18. Reconnect PCM connector A (73P).
19. Turn the ignition switch ON (II).
20. Reset the PCM with the HDS.
21. Do the PCM idle learn procedure.
22. Start the engine. Hold the engine speed at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on, then let it idle.
23. Test-drive under the following conditions.
- Engine coolant temperature more than 158 °F (70 °C)
- A/T in D position
- Engine speed at 2,000 - 3,000 rpm
- Drive about 10 minutes, then decelerate (with the throttle fully closed) for 5 seconds

24. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P0137 and/or P0157* 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 25.

25. Monitor the OBD STATUS for DTC P0137 and/or P0157* in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - Troubleshooting is complete.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the secondary (Sensor 2) and the PCM, then go to step 1. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step 22 and recheck.

26. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
27. Start the engine. Hold the engine speed at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on, then let it idle.
28. Test-drive under the following conditions.
- Engine coolant temperature more than 158 °F (70 °C)
- A/T in D position
- Engine speed at 2,000 - 3,000 rpm
- Drive about 10 minutes, then decelerate (with the throttle fully closed) for 5 seconds

29. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P0137 and/or P0157* 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.