DTC Troubleshooting: P0138, P0158
DTC P0138: Rear Secondary HO2S (Bank 1, Sensor 2) Circuit High Voltage
DTC P0158: Front Secondary HO2S (Bank 2, Sensor 2) Circuit High Voltage
NOTE:
Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
Information marked with an asterisk (*) applies to the front bank (Bank 2).

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0138 Rear Secondary HO2S (Bank 1, Sensor 2) Circuit High Voltage
     
P0158 Front Secondary HO2S (Bank 2, Sensor 2) Circuit High Voltage
     

1.
Problem verification:

Problem verification
?1.
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, then let it idle.
Signal
Current conditions
Values
Unit
ECT SENSOR 1
    
ENGINE SPEED
    

?4.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
HO2S B1 S2
More than 1.27
V
    
HO2S B2 S2*
More than 1.27
V
    

Do the current condition(s) match the threshold?

     
YES
     
     
     
The failure is duplicated. Go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the PCM.?
2.
Determine possible failure area (Secondary HO2S (Sensor 2), others):

Determine possible failure area (Secondary HO2S (Sensor 2), others)
?1.
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.
Rear bank (Bank 1):
Terminal A
Secondary HO2S (Sensor 2) 4P connector No. 1 (WHT)
Terminal B
Secondary HO2S (Sensor 2) 4P connector No. 2 (GRN)

Front bank (Bank 2) (J35Y1 engine):
Terminal A
Secondary HO2S (Sensor 2) 4P connector No. 1 (BLU)
Terminal B
Secondary HO2S (Sensor 2) 4P connector No. 2 (YEL)

Front bank (Bank 2) (J35Y2 engine):
Terminal A
Secondary HO2S (Sensor 2) 4P connector No. 1 (YEL)
Terminal B
Secondary HO2S (Sensor 2) 4P connector No. 2 (BLU)


?4.
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 B1 S2
More than 1.27
V
    
HO2SB2 S2*
More than 1.27
V
    

Do the current condition(s) match the threshold?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
3.
Open wire check (SO2B1 (SO2B2)* line):

Open wire check (SO2B1 (SO2B2)* line)
?1.
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.
Connect terminals A and B with a jumper wire.
Rear bank (Bank 1):
Terminal A
Rear secondary HO2S (Bank 1, Sensor 2) 4P connector No. 2 (GRN)
Terminal B
Body ground

Front bank (Bank 2) (J35Y1 engine):
Terminal A
Front secondary HO2S (Bank 2, Sensor 2) 4P connector No. 1 (BLU)
Terminal B
Body ground

Front bank (Bank 2) (J35Y2 engine):
Terminal A
Front secondary HO2S (Bank 2, Sensor 2) 4P connector No. 2 (BLU)
Terminal B
Body ground


?4.
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 B1 S2
More than 1.27
V
    
HO2S B2 S2*
More than 1.27
V
    

Do the current condition(s) match the threshold?

     
YES
     
     
     
The SO2B1 (SO2B2)* wire is OK. Go to step 4.
     
NO
     
     
     
Repair an open in the SO2B1 (SO2B2)* wire between the PCM (C30 (C31)*) and secondary HO2S (Sensor 2), then do the repair verification.
4.
Open wire check (SO2B1 (SO2B2)* line):

Open wire check (SO2B1 (SO2B2)* line)
?1.
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
OFF mode
 
Rear secondary HO2S (Bank 1, Sensor 2) 4P connector terminal No. 2: jumped to body ground
 
Front secondary HO2S (Bank 2, Sensor 2) 4P connector terminal No. 1: jumped to body ground*
 
PCM connector C (51P): disconnected
Test circuit
SO2B1 (SO2B2)*
Test point 1
PCM connector C (51P) No. 30 (GRN)
 
PCM connector C (51P) No. 31 (BLU)*
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
The SO2B1 (SO2B2)* 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.
     
NO
     
     
     
Repair an open in the SO2B1 (SO2B2)* wire between the PCM (C30 (C31)*) and secondary HO2S (Sensor 2), then do the repair verification.
Repair verification (OBD STATUS check):

?1.
Reconnect all connectors.

?2.
Press the engine start/stop button to select the ON mode.

?3.
Exit the SCS mode with the HDS.


?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.

?7.
Test-drive under these conditions:
Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
A/T in D, M/T in 4th or 5th
Engine speed between 1,500?3,000 rpm
Drive 5 seconds or more

Signal
Current conditions
Values
Unit
ECT SENSOR 1
    
ENGINE SPEED
    

?8.
Monitor the OBD STATUS for DTC P0138 and/or P0158* in the DTCs MENU with the HDS.
DTC Description
OBD STATUS
P0138 Rear Secondary HO2S (Bank 1, Sensor 2) Circuit High Voltage
 
P0158 Front Secondary HO2S (Bank 2, Sensor 2) Circuit High Voltage
 


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

     
PASSED (P0138)
     
     
     
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.?
     
PASSED (P0158)
     
     
     
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 (P0138)
     
     
     
Go to step 1 and recheck. If the PCM was updated, substitute a known-good PCM, then check the OBD STATUS again.
     
FAILED (P0158)
     
     
     
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.