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.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0137 Secondary HO2S (Sensor 2) Circuit Low Voltage
      

1.
Problem verification:

Problem verification
?1.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Start the engine. Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on.

?4.
Monitor the OBD STATUS for DTC P0137 in the DTCs MENU with the HDS.
DTC Description
OBD STATUS
P0137 Secondary HO2S (Sensor 2) Circuit Low Voltage
 

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):

Determine possible failure area (Secondary HO2S (Sensor 2), others)
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connector.

?3.
Connect terminals A and B with a jumper wire.
Terminal A
Secondary HO2S (Sensor 2) 4P connector No. 1 (ORN)
Terminal B
Secondary HO2S (Sensor 2) 4P connector No. 2 (WHT)


?4.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?5.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
HO2S S2 OUTPUT VOLTAGE
Less than 0.12
V
    

Do the current condition(s) match the threshold?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
3.
Determine possible failure area (short in SO2 line, short in SO2SG/SO2 SG line):

Determine possible failure area (short in SO2 line, short in SO2SG/SO2 SG line)
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

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

?3.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?4.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
HO2S S2 OUTPUT VOLTAGE
About 5.0
V
    

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):

Shorted wire check (SO2SG/SO2 SG line)
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Jump the SCS line with the HDS.


?3.
Disconnect the following connector.

?4.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0) or OFF mode
 
PCM connector C (51P): disconnected
 
Secondary HO2S (Sensor 2) 4P connector: disconnected
Test circuit
SO2SG
Test point 1
PCM connector C (51P) No. 39 (GRN/BLK)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short in the SO2SG/SO2 SG wire between the PCM (C39) and secondary HO2S (Sensor 2), then do the repair verification.
     
NO
     
     
     
The SO2SG/SO2 SG wire is OK. Go to step 5.
5.
Shorted wire check (SO2 line):

Shorted wire check (SO2 line)
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Jump the SCS line with the HDS.


?3.
Disconnect the following connector.

?4.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0) or OFF mode
 
PCM connector C (51P): disconnected
 
Secondary HO2S (Sensor 2) 4P connector: disconnected
Test circuit
SO2
Test point 1
PCM connector C (51P) No. 38 (WHT)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short in the SO2 wire between the PCM (C38) and secondary HO2S (Sensor 2), then do the repair verification.
     
NO
     
     
     
The SO2 wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM, then do the repair verification.
Repair verification (OBD STATUS check):

?1.
Reconnect all connectors.

?2.
Exit the SCS mode with the HDS.


?3.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?4.
Reset the PCM with the HDS.


?5.
Do the PCM idle learn procedure.

?6.
Start the engine, and let it idle without load ( A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.

?7.
Monitor the OBD STATUS for DTC P0137 in the DTCs MENU with the HDS.
DTC Description
OBD STATUS
P0137 Secondary HO2S (Sensor 2) Circuit Low Voltage
 


Does the HDS indicate PASSED, FAILED, EXECUTING, or OUT OF CONDITION?

     
PASSED
     
     
     
Troubleshooting is complete. If the PCM was substituted, replace the original PCM. 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, 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.