DTC Troubleshooting: P0134, P0154
DTC P0134: Rear A/F Sensor (Bank 1, Sensor 1) Heater System Malfunction
DTC P0154: Front A/F Sensor (Bank 2, Sensor 1) Heater System Malfunction
NOTE:
Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
If DTC P2251 and/or P2254* is stored at the same time as DTC P0134 and/or P0154*, troubleshoot DTC P2251 and/or P2254* first, then recheck for P0134 and/or P0154*.
Information marked with an asterisk (*) applies to the front bank (Bank 2).

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0134 Rear A/F Sensor (Bank 1, Sensor 1) Heater System Malfunction
      
P0154 Front A/F Sensor (Bank 2, Sensor 1) Heater System Malfunction
     

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, and let it idle without load (A/T in P or N, M/T in neutral) for at least 1 minute.

?4.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0134 Rear A/F Sensor (Bank 1, Sensor 1) Heater System Malfunction
      
P0154 Front A/F Sensor (Bank 2, Sensor 1) Heater System Malfunction
     

Is DTC P0134 and/or P0154* indicated?

     
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 the A/F sensor (Sensor 1), the PGM-FI subrelay, and the PCM.?
2.
Open wire check (VSB1 (VSB2)* line):

Open wire check (VSB1 (VSB2)* 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 connectors.

?4.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
 
PCM connector C (51P): disconnected
 
A/F sensor (Sensor 1) 8P connector: disconnected
Test circuit
VSB1 (VSB2)*
Test point 1
Rear A/F sensor (Bank 1, Sensor 1) 8P connector No. 8 (LT GRN)
 
Front A/F sensor (Bank 2, Sensor 1) 8P connector No. 8 (WHT)*
Test point 2
PCM connector C (51P) No. 25 (LT GRN)
 
PCM connector C (51P) No. 28 (WHT)*


Is there continuity?

     
YES
     
     
     
The VSB1 (VSB2)* wire is OK. Go to step 3.
     
NO
     
     
     
Repair an open in the VSB1 (VSB2)* wire between the PCM (C25 (C28)*) and the A/F sensor (Sensor 1), then do the repair verification.
3.
PCM output voltage check:

PCM output voltage check
?1.
Reconnect PCM connector C (51P).

?2.
Exit the SCS mode with the HDS.


?3.
Start the engine, and let it idle without load (A/T in P or N, M/T in neutral) for at least 1 minute.

?4.
Measure the voltage between test point 1 and 2.
Test condition
Running
 
PCM connector C (51P): connected
 
A/F sensor (Sensor 1) 8P connector: disconnected
Test circuit
VSB1 (VSB2)*
Test point 1
Rear A/F sensor (Bank 1, Sensor 1) 8P connector No. 8 (LT GRN)
 
Front A/F sensor (Bank 2, Sensor 1) 8P connector No. 8 (WHT)*
Test point 2
Body ground


Is there about 0.2 V or less?

     
YES
     
     
     
Update the PCM if it does not have the latest software, or substitute a known-good PCM, then do the repair verification.
     
NO
     
     
     
Repair verification (OBD STATUS check):

?1.
Press the engine start/stop button to select the OFF mode.

?2.
Reconnect all connectors.

?3.
Exit the SCS mode with the HDS.


?4.
Press the engine start/stop button to select the ON mode.

?5.
Reset the PCM with the HDS.


?6.
Do the PCM idle learn procedure.

?7.
Monitor the OBD STATUS for DTC P0134 and/or P0154* in the DTCs MENU with the HDS.
DTC Description
OBD STATUS
P0134 Rear A/F Sensor (Bank 1, Sensor 1) Heater System Malfunction
 
P0154 Front A/F Sensor (Bank 2, Sensor 1) Heater System Malfunction
 


Does the HDS indicate PASSED, FAILED, or NOT COMPLETED?

     
PASSED (P0134)
     
     
     
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 (P0154)
     
     
     
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 (P0134)
     
     
     
Go to step 1 and recheck. If the PCM was updated, substitute a known-good PCM, then check the OBD STATUS again.
     
FAILED (P0154)
     
     
     
Go to step 1 and recheck. If the PCM was updated, substitute a known-good PCM, then check the OBD STATUS again.
     
NOT COMPLETED
     
     
     
Keep the test condition until a result comes on.