DTC Troubleshooting: P0137
DTC P0137: Secondary HO2S (Sensor 2) Circuit Low Voltage
NOTE: Before you troubleshoot, review the general troubleshooting information.

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

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Start the engine.

?4.
Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on.

?5.
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 on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot. If the HDS indicates EXECUTING, keep idling until a result comes on. If the HDS indicates OUT OF CONDITION, go to step 1-4 and recheck.?
2.
Determine possible failure area (secondary HO2S (Sensor 2), others):

Determine possible failure area (secondary HO2S (Sensor 2), others)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Secondary HO2S (Sensor 2) 4P connector

?3.
Turn the vehicle to the ON mode.

?4.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
HO2S S2
Less than 0.02
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 line):

Determine possible failure area (short in SO2 line, short in SO2SG line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Secondary HO2S (Sensor 2) 4P connector: disconnected
Test point 1
Secondary HO2S (Sensor 2) 4P connector (female terminals) No. 2:
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Go to step 5.
4.
Shorted wire check (SO2 line):

Shorted wire check (SO2 line)
?1.
Jump the SCS line with the HDS, and wait more than 1 minute.


?2.
Disconnect the following connector.
PCM connector No. 1 (96P)

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Secondary HO2S (Sensor 2) 4P connector: disconnected
 
PCM connector No. 1 (96P): disconnected
Test point 1
Secondary HO2S (Sensor 2) 4P connector (female terminals) No. 2:
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short in the SO2 wire between PCM connector No. 1 terminal No. 22 and secondary HO2S (Sensor 2).?
     
NO
     
     
     
The SO2 wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC P0137 goes away and the PCM was substituted, replace the original PCM.?
5.
Shorted wire check (SO2SG line):

Shorted wire check (SO2SG line)
?1.
Jump the SCS line with the HDS, and wait more than 1 minute.


?2.
Disconnect the following connector.
PCM connector No. 1 (96P)

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Secondary HO2S (Sensor 2) 4P connector: disconnected
 
PCM connector No. 1 (96P): disconnected
Test point 1
Secondary HO2S (Sensor 2) 4P connector (female terminals) No. 1:
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short in the SO2SG wire between PCM connector No. 1 terminal No. 24 and secondary HO2S (Sensor 2).?
     
NO
     
     
     
The SO2SG wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC P0137 goes away and the PCM was substituted, replace the original PCM.?