DTC Troubleshooting: P0135
DTC P0135: A/F Sensor (Sensor 1) Heater Circuit Malfunction
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0135 A/F Sensor (Sensor 1) Heater Circuit Malfunction
     

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.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0135 A/F Sensor (Sensor 1) Heater Circuit Malfunction
     

Is DTC P0135 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 ETCS control relay, 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.
DTC check:

DTC check
?1.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P1658 ETCS Control Relay ON Malfunction
     
P1659 ETCS Control Relay OFF Malfunction
     

Is DTC P1658 and/or P1659 indicated?

     
YES
     
     
     
Go to the indicated DTC's troubleshooting.?
     
NO
     
     
     
Go to step 3.
3.
Fuse check:

Fuse check
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Check the following fuse.
Fuse
No. B30 (10 A)
Location
Under-hood fuse/relay box

Is the fuse OK?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Go to step 9.
4.
A/F sensor (Sensor 1) internal heater resistance check:

A/F sensor (Sensor 1) internal heater resistance check
?1.
Disconnect the following connector.
A/F sensor (Sensor 1) 4P connector

?2.
At the sensor side, measure the resistance between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
A/F sensor (Sensor 1) 4P connector: disconnected
Test point 1
A/F sensor (Sensor 1) 4P connector No. 3 (A/F sensor (Sensor 1) side)
Test point 2
A/F sensor (Sensor 1) 4P connector No. 4 (A/F sensor (Sensor 1) side)


Is there 2.0?2.7 ? at room temperature?

     
YES
     
     
     
Go to step 5.
     
NO
     
     
     
5.
A/F sensor (Sensor 1) internal circuit check:

A/F sensor (Sensor 1) internal circuit check
?1.
Check for continuity between the following test points and the A/F sensor (Sensor 1) 4P connector No. 1 individually.
Test condition
Vehicle OFF (LOCK) mode
 
A/F sensor (Sensor 1) 4P connector: disconnected

Connector
Terminal
A/F sensor (Sensor 1)
(A/F sensor (Sensor 1) side)
No. 3
No. 4


Is there continuity?

     
YES
     
     
     
     
NO
     
     
     
Go to step 6.
6.
Shorted wire check (AFHT line):

Shorted wire check (AFHT line)
?1.
Jump the SCS line with the HDS.


?2.
Disconnect the following connector.
PCM connector C (51P)

?3.
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
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
Repair a short in the AFHT wire between the PCM (C7) and the A/F sensor (Sensor 1).?
     
NO
     
     
     
The AFHT wire is not shorted. Go to step 7.
7.
Open wire check (AFHT line):

Open wire check (AFHT 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. 4
Test point 2


Is there continuity?

     
YES
     
     
     
The AFHT wire is OK. Go to step 8.
     
NO
     
     
     
Repair an open in the AFHT wire between the PCM (C7) and the A/F sensor (Sensor 1).?
8.
Open wire check (IGPS(LAF) line):

Open wire check (IGPS(LAF) line)
?1.
Turn the vehicle to the ON mode.

?2.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON 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. 3
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The IGPS(LAF) wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If DTC P0135 goes away and the PCM was updated, troubleshooting is complete. If DTC P0135 goes away and the PCM was substituted, replace the original PCM.?
     
NO
     
     
     
Repair an open in the IGPS(LAF) wire between the A/F sensor (Sensor 1) and the No. B30 (10 A) fuse in the under-hood fuse/relay box.?
9.
Shorted wire check (IGPS(LAF) line):

Shorted wire check (IGPS(LAF) line)
?1.
Remove the No. B30 (10 A) fuse from the under-hood fuse/relay box.

?2.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
No. B30 (10 A) fuse: removed
 
A/F sensor (Sensor 1) 4P connectors: disconnected
Test point 1
A/F sensor (Sensor 1) 4P connector No. 3
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short in the IGPS(LAF) wire between the A/F sensor (Sensor 1) and the No. B30 (10 A) fuse in the under-hood fuse/relay box. Also replace the No. B30 (10 A) fuse.?
     
NO
     
     
     
The IGPS(LAF) wire is OK. Replace the No. B30 (10 A) fuse in the under-hood fuse/relay box and recheck. If the fuse is blown again, replace the under-hood fuse/relay box.?