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Home >> Honda >> 2021 >> Insight LX >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTC Diagnostics (1 Of 4) >> DTC Troubleshooting >> DTC P0135
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DTC 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    

DTC (PGM-FI)

  1. Problem verification

    -1. Turn the vehicle to the ON mode.

    -2. Clear the DTC with the HDS.

    -3. Turn the vehicle to the OFF (LOCK) mode.

    -4. Enter the maintenance mode, then start the engine .

    -5. Hold the engine speed at 3000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.

    -6. Check for Pending or Confirmed DTCs with the HDS.

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

    DTC (PGM-FI)

    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) 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

    -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    

    DTC (PGM-FI)

    Is DTC P1658 and/or P1659 indicated?

    YES 

    Go to the indicated DTCs troubleshooting.

    NO 

    Go to step 3.

  3. Fuse check

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

    -2. Check the No. B11 fuse .

    Is the fuse OK?

    YES 

    Go to step 4.

    NO 

    Repair a short in the IGPS(LAF)/IGP(LAF) wire between the No. B11 fuse and the A/F sensor (Sensor 1). Also replace the No. B11 fuse.

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

    -1. Disconnect the following connector.

    A/F sensor (Sensor 1) 6P 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) 6P connector: disconnected
    Test point 1 A/F sensor (Sensor 1) 6P connector (male terminals) No. 2 (sensor side):
    Test point 2 A/F sensor (Sensor 1) 6P connector (male terminals) No. 3 (sensor side):
    GHH384862Courtesy of HONDA, U.S.A., INC.

    Is there 2.8-4.5 Ω at room temperature?

    YES 

    Go to step 5.

    NO 

    Replace the A/F sensor (Sensor 1) .

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

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

    Test condition Vehicle OFF (LOCK) mode
      A/F sensor (Sensor 1) 6P connector: disconnected
    Connector Terminal
    A/F sensor (Sensor 1) 6P connector (male terminals) (sensor side): No. 2
    No. 3
    No. 4
    No. 5
    No. 6
    GHH384864Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Replace the A/F sensor (Sensor 1) .

    NO 

    Go to step 6.

  6. A/F sensor (Sensor 1) internal circuit check 2

    -1. Check for continuity between the following test points and the A/F sensor (Sensor 1) 6P connector No. 3 individually.

    Test condition Vehicle OFF (LOCK) mode
      A/F sensor (Sensor 1) 6P connector: disconnected
    Connector Terminal
    A/F sensor (Sensor 1) 6P connector (male terminals) (sensor side): No. 2
    No. 4
    No. 5
    No. 6
    GHH384866Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Replace the A/F sensor (Sensor 1) .

    NO 

    Go to step 7.

  7. Shorted wire check (AFHT N line)

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

    -2. Disconnect the following connector.

    PCM connector E (80P)

    -3. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      A/F sensor (Sensor 1) 6P connector: disconnected
      PCM connector E (80P): disconnected
    Test point 1 PCM connector E (80P) No. 13
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the AFHT N wire between the PCM (E13) and the A/F sensor (Sensor 1).

    NO 

    The AFHT N wire is not shorted. Go to step 8.

  8. Open wire check (AFHT N line)

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

    Test condition Vehicle OFF (LOCK) mode
      A/F sensor (Sensor 1) 6P connector: disconnected
      PCM connector E (80P): disconnected
    Test point 1 A/F sensor (Sensor 1) 6P connector (female terminals) No. 2:
    Test point 2 PCM connector E (80P) No. 13
    GHH384868Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    The AFHT N wire is OK. Go to step 9.

    NO 

    Repair an open in the AFHT N wire between the PCM (E13) and the A/F sensor (Sensor 1).

  9. Open wire check (IGPS(LAF)/IGP(LAF) line)

    -1. Exit the SCS mode with the HDS.

    -2. Turn the vehicle to the ON mode.

    -3. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
      A/F sensor (Sensor 1) 6P connector: disconnected
      PCM connector E (80P): disconnected
    Test point 1 A/F sensor (Sensor 1) 6P connector (female terminals) No. 3:
    Test point 2 Body ground
    GHH384870Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    The IGPS(LAF)/IGP(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 , then recheck. If DTC P0135 goes away and the PCM was substituted, replace the original PCM .

    NO 

    Repair an open in the IGPS(LAF)/IGP(LAF) wire between the No. B11 fuse and the A/F sensor (Sensor 1).

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