DTC Troubleshooting: P1157
DTC P1157: A/F Sensor (Sensor 1) AFS Circuit High Voltage
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P1157 A/F Sensor (Sensor 1) AFS Circuit High 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, and wait for 1 minute.

?4.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P1157 A/F Sensor (Sensor 1) AFS Circuit High Voltage
     

Is DTC P1157 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) and the PCM. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.?
2.
Open wire check (AFS+ line):

Open wire check (AFS+ line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Jump the SCS line with the HDS, and wait more than 1 minute.


?3.
Disconnect the following connectors.
A/F sensor (Sensor 1) 4P connector
PCM connector C (51P)

?4.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
A/F sensor (Sensor 1) 4P connector: disconnected
 
PCM connector C (51P): disconnected
Test point 1
A/F sensor (Sensor 1) 4P connector No. 2
Test point 2
PCM connector C (51P) No. 48


Is there continuity?

     
YES
     
     
     
The AFS+ wire is OK. Go to step 3.
     
NO
     
     
     
Repair an open in the AFS+ wire between the PCM (C48) and the A/F sensor (Sensor 1).?
3.
Open wire check (AFS- line):

Open wire check (AFS- line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
A/F sensor (Sensor 1) 4P connector: disconnected
 
PCM connector C (51P): disconnected
Test point 1
A/F sensor (Sensor 1) 4P connector No. 1
Test point 2
PCM connector C (51P) No. 47


Is there continuity?

     
YES
     
     
     
The AFS- wire is OK. Go to step 4.
     
NO
     
     
     
Repair an open in the AFS- wire between the PCM (C47) and the A/F sensor (Sensor 1).?
4.
A/F sensor (Sensor 1) check (substitution):

A/F sensor (Sensor 1) check (substitution)
?1.
Substitute a known-good A/F sensor (Sensor 1).

?2.
Reconnect all connectors.

?3.
Turn the vehicle to the ON mode.

?4.
Reset the PCM with the HDS.


?5.
Do the PCM idle learn procedure.

?6.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P1157 A/F Sensor (Sensor 1) AFS Circuit High Voltage
     

Is DTC P1157 indicated?

     
YES
     
     
     
The failure is duplicated. Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If DTC P1157 goes away and the PCM was updated, troubleshooting is complete. If DTC P1157 goes away and the PCM was substituted, replace the original PCM.?
     
NO