DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P0137

DTC P0137 : Secondary HO2S (Sensor 2) Circuit Low Voltage

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How to Troubleshoot the Fuel And Emissions Systems.

1. Problem verification:

-1. Turn the ignition switch to ON (II).

-2. Clear the DTC with the HDS. How to Troubleshoot the Fuel And Emissions Systems

-3. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on.

-4. Monitor the OBD STATUS for DTC P0137 in the DTCs MENU with the HDS.





Does the HDS indicate FAILED?
-YES- The failure is duplicated. Go to step 2.
-NO- If the HDS indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the PCM. If the HDS indicates EXECUTING, keep idling until a result comes on. If the HDS indicates OUT OF CONDITION, go to step 1-3 and recheck.

2. Determine possible failure area (secondary HO2S (Sensor 2), others):

-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.





-3. Connect terminals A and B with a jumper wire.









-4. Turn the ignition switch to ON (II).

-5. Check the parameter(s) below with the HDS.





Do the current condition(s) match the threshold?
-YES- Go to step 3.
-NO- Replace secondary HO2S (Sensor 2) Secondary HO2S Removal And Installation, then do the repair verification.

3. Determine possible failure area (short in SO2 line, short in SO2SG line):

-1. Turn the ignition switch to LOCK (0).

-2. Remove the jumper wire from the secondary HO2S (Sensor 2) 4P connector.

-3. Turn the ignition switch to ON (II).

-4. Check the parameter(s) below with the HDS.





Do the current condition(s) match the threshold?
-YES- Go to step 4.
-NO- Go to step 5.

4. Shorted wire check (SO2SG/SO2 SG line):

-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.





-4. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- Repair a short in the SO2SG/SO2 SG wire between the PCM (C47) and secondary HO2S (Sensor 2), then do the repair verification.
-NO- The SO2SG/SO2 SG wire is OK. Update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then do the repair verification.

5. Shorted wire check (SO2 line):

-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.





-4. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- Repair a short in the SO2 wire between the PCM (B46) and secondary HO2S (Sensor 2), then do the repair verification.
-NO- The SO2 wire is OK. Update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then do the repair verification.

Repair verification (OBD STATUS check):

-1. Reconnect all connectors.

-2. Turn the ignition switch to ON (II).

-3. Reset the PCM with the HDS How to Troubleshoot the Fuel And Emissions Systems.

-4. Do the PCM idle learn procedure PCM Idle Learn Procedure.

-5. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.

-6. Monitor the OBD STATUS for DTC P0137 in the DTCs MENU with the HDS.






Does the HDS indicate PASSED, FAILED, EXECUTING, or OUT OF CONDITION?
-PASSED- Troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.
-FAILED- Go to step 1 and recheck. If the PCM was updated, substitute a known-good PCM Service and Repair, then check the OBD STATUS again.
-EXECUTING- Keep the test condition until a result comes on.
-OUT OF CONDITION- Meet the test condition, and check the OBD STATUS again.