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
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. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on.

?4.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
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 relay circuit board (PGM-FI subrelay circuit), 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.?
2.
DTC check:

DTC check
?1.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
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. A11 (7.5 A)
Location
Under-hood fuse/relay box

Is the fuse OK?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Repair a short in the IGPS(LAF) wire between the No. A11 (7.5 A) fuse in the under-hood fuse/relay box and the A/F sensor (Sensor 1). Also replace the No. A11 (7.5 A) fuse.?
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 (male terminals) No. 3 (A/F sensor (Sensor 1) side):
Test point 2
A/F sensor (Sensor 1) 4P connector (male terminals) No. 4 (A/F sensor (Sensor 1) side):


Is there 2.2?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.
At the sensor side, check for continuity under the following conditions.
Test condition
Vehicle OFF (LOCK) mode
 
A/F sensor (Sensor 1) 4P connector: disconnected

Test condition
Vehicle OFF (LOCK) mode
 
A/F sensor (Sensor 1) 4P connector: disconnected
Test point 1
A/F sensor (Sensor 1) 4P connector (male terminals) No. 3 (A/F sensor (Sensor 1) side):
A/F sensor (Sensor 1) 4P connector (male terminals) No. 4 (A/F sensor (Sensor 1) side):
Test point 2
A/F sensor (Sensor 1) 4P connector (male terminals) No. 1 (A/F sensor (Sensor 1) side):


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, and wait more than 1 minute.


?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
PCM connector C (51P) No. 7
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 (female terminals) No. 3:
Test point 2
PCM connector C (51P) No. 7


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)/LAF+ line):

Open wire check (IGPS(LAF)/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 (female terminals) No. 4:
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The IGPS(LAF)/LAF+ wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good PCM.?
     
NO
     
     
     
Repair an open in the IGPS(LAF)/LAF+ wire between the A/F sensor (Sensor 1) and the relay circuit board (PGM-FI subrelay circuit).?