DTC P0135

DTC P0135  : A/F Sensor (Sensor 1) Heater Circuit Malfunction

NOTE:  Before you troubleshoot, review the general troubleshooting information .

DTC (PGM-FI)

1. 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 (CVT in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.

   -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. Fuse check

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Check the following fuse.

   Fuse	No. B30 (7.5 A)
   Location	Under-hood fuse/relay box

   Is the fuse OK?

   YES 

   Go to step 3.

   NO 

   Go to step 8.

3. 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)

   Courtesy of HONDA, U.S.A., INC.

   Is there 2.0-2.7 Ω at room temperature?

   YES 

   Go to step 4.

   NO 

   Replace the A/F sensor (Sensor 1) .

4. A/F sensor (Sensor 1) internal circuit check

   -1. Check for continuity between the following test points and 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

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Replace the A/F sensor (Sensor 1) .

   NO 

   Go to step 5.

5. Shorted wire check (AFHT line)

   -1. Jump the SCS line with the HDS.

   -2. Disconnect the following connector.

   PCM connector B (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 B (51P): disconnected
   Test point 1	PCM connector B (51P) No. 19
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short in the AFHT wire between the PCM (B19) and A/F sensor (Sensor 1).

   NO 

   The AFHT wire is not shorted. Go to step 6.

6. 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 B (51P): disconnected
   Test point 1	A/F sensor (Sensor 1) 4P connector No. 4
   Test point 2	PCM connector B (51P) No. 19

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The AFHT wire is OK. Go to step 7.

   NO 

   Repair an open in the AFHT wire between the PCM (B19) and A/F sensor (Sensor 1).

7. Open wire check (IGPS (LAF+)/FI SUB RLY OUT 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 B (51P): disconnected
   Test point 1	A/F sensor (Sensor 1) 4P connector No. 3
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there battery voltage?

   YES 

   The IGPS (LAF+)/FI SUB RLY OUT 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+)/FI SUB RLY OUT wire between A/F sensor (Sensor 1) and the No. B30 (7.5 A) fuse in the under-hood fuse/relay box.

8. Shorted wire check (IGPS (LAF+)/FI SUB RLY OUT line)

   -1. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	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

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair a short in the IGPS (LAF+)/FI SUB RLY OUT wire between A/F sensor (Sensor 1) and the No. B30 (7.5 A) fuse in the under-hood fuse/relay box. Also replace the No. B30 (7.5 A) fuse.

   NO 

   The IGPS (LAF+) wire is OK. Replace the No. B30 (7.5 A) fuse in the under-hood fuse/relay box and recheck. If the fuse is blown again, replace the under-hood fuse/relay box .