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Radiator Fan High Speed Circuit Troubleshooting

Radiator Fan High Speed Circuit Troubleshooting 

  1. Fuse check

    -1. Check the following fuses.

    Fuse Location
    No. A1-3 (30 A) Under-hood fuse/relay box
    No. B25 (7.5 A) Fuse/relay holder A
    No. D9 (10 A) Under-dash fuse/relay box

    Are the fuses OK?

    YES 

    Reinstall the fuses, then go to step 2.

    NO 

    Replace the fuse (s), and recheck. If the fuse (s) blows again, repair the short to ground on the No. A1-3 (30 A) fuse, the No. B25 (7.5 A) fuse, and/or the No. D9 (10 A) fuse circuit (s).

  2. Radiator fan and fan control relays check

    -1. Check the following relays.

    Relay Location
    Radiator fan relay Under-hood fuse/relay box
    Fan control relay Relay holder F

    Are the relays OK?

    YES 

    Go to step 3.

    NO 

    Replace the relay (s).

  3. Open wire check (+B MAIN FAN line)

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

    Test condition Vehicle OFF (LOCK) mode
    Radiator fan relay: disconnected
    Test point 1 Radiator fan relay 4P socket (female terminals) No. 1:
    Test point 2 Body ground
    GHH426669Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 4.

    NO 

    Repair an open in the +B MAIN FAN wire between the radiator fan relay and the No. A1-3 (30 A) fuse.

  4. Determine possible failure area (GND line, others)

    -1. Connect terminals A and B with a jumper wire.

    Terminal A Fan control relay 5P socket (female terminals) No. 1:
    Terminal B Fan control relay 5P socket (female terminals) No. 2:
    GHH426672Courtesy of HONDA, U.S.A., INC.

    -2. Connect terminals A and B with a jumper wire.

    Terminal A Radiator fan relay 4P socket (female terminals) No. 1:
    Terminal B Radiator fan relay 4P socket (female terminals) No. 2:
    GHH426675Courtesy of HONDA, U.S.A., INC.

    Does the radiator fan run at high speed?

    YES 

    Remove the jumper wires, then go to step 9.

    NO 

    Remove the jumper wires, then go to step 5.

  5. Radiator fan motor operation check

    -1. Test the radiator fan motor .

    Is the motor OK?

    YES 

    Go to step 6.

    NO 

    Replace the radiator fan motor .

  6. Open wire check (GND line)

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

    Test condition Vehicle OFF (LOCK) mode
    Radiator fan relay: disconnected
      Fan control relay: disconnected
    Test point 1 Fan control relay 5P socket (female terminals) No. 2:
    Test point 2 Body ground
    GHH426677Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Go to step 7.

    NO 

    Repair an open in the GND wire between the fan control relay and ground G351.

  7. Open wire check (MAIN FAN MOTOR line)

    -1. Disconnect the following connector.

    Radiator fan motor 2P connector

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

    Test condition Vehicle OFF (LOCK) mode
    Radiator fan relay: disconnected
      Fan control relay: disconnected
      Radiator fan motor 2P connector: disconnected
    Test point 1 Radiator fan relay 4P socket (female terminals) No. 2:
    Test point 2 Radiator fan motor 2P connector (female terminals) No. 1:
    GHH426680Courtesy of HONDA, U.S.A., INC.
    GHH426681Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Go to step 8.

    NO 

    Repair an open in the MAIN FAN MOTOR wire between the radiator fan relay and the radiator fan motor.

  8. Open wire check (FAN HI/LO RLY COM line)

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

    Test condition Vehicle OFF (LOCK) mode
    Radiator fan relay: disconnected
    Fan control relay: disconnected
      Radiator fan motor 2P connector: disconnected
    Test point 1 Fan control relay 5P socket (female terminals) No. 1:
    Test point 2 Radiator fan motor 2P connector (female terminals) No. 2:
    GHH426684Courtesy of HONDA, U.S.A., INC.
    GHH426685Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Check for poor connections or loose terminals at the under-hood fuse/relay box and the radiator fan motor.

    NO 

    Repair an open in the FAN HI/LO RLY COM wire between the fan control relay 5P and the radiator fan motor.

  9. Open wire check (IG2 A/C line)

    -1. Turn the vehicle to the ON mode.

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

    Test condition Vehicle ON mode
    Radiator fan relay: disconnected
      Fan control relay: disconnected
    Test point 1 Radiator fan relay 4P socket (female terminals) No. 3:
    Test point 2 Body ground
    GHH426687Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 10.

    NO 

    Repair an open in the IG2 A/C wire between the radiator fan relay and the No. D9 (10 A) fuse.

  10. Open wire check (IGP2 SUB line)

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

    Test condition Vehicle ON mode
    Radiator fan relay: disconnected
      Fan control relay: disconnected
    Test point 1 Fan control relay 5P socket (female terminals) No. 3:
    Test point 2 Body ground
    GHH426689Courtesy of HONDA, U.S.A., INC.

    Is there battery voltage?

    YES 

    Go to step 11.

    NO 

    Repair an open in the IGP2 SUB wire between the fan control relay and the No. B25 (7.5 A) fuse.

  11. Open wire check (FAN LO SIGNAL line)

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

    -2. Connect the HDS to the DLC .

    -3. Jump the SCS line with the HDS, and wait more than 1 minute.

    NOTE:  This step must be done to protect the PCM from damage.

    -4. Disconnect the following connector.

    1.5 L engine: PCM connector A (50P)
    2.4 L engine: PCM connector A (51P)

    -5. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    Radiator fan relay: disconnected
    Fan control relay: disconnected
      PCM connector A (50P or 51P): disconnected
    1.5 L engine:  
    Test point 1 Radiator fan relay 4P socket (female terminals) No. 4:
    Test point 2 PCM connector A (50P) No. 17
    2.4 L engine:
    Test point 1 Radiator fan relay 4P socket (female terminals) No. 4:
    Test point 2 PCM connector A (51P) No. 9
    GHH426692Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Go to step 12.

    NO 

    Repair an open in the FAN LO SIGNAL wire between the radiator fan relay and the PCM.

  12. Open wire check (FAN HI SIGNAL line)

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

    Test condition Vehicle OFF (LOCK) mode
    Radiator fan relay: disconnected
    Fan control relay: disconnected
      PCM connector A (50P or 51P): disconnected
    1.5 L engine:  
    Test point 1 Fan control relay 5P socket (female terminals) No. 5:
    Test point 2 PCM connector A (50P) No. 18
    2.4 L engine:
    Test point 1 Fan control relay 5P socket (female terminals) No. 5:
    Test point 2 PCM connector A (51P) No. 10
    GHH426695Courtesy of HONDA, U.S.A., INC.

    Is there continuity?

    YES 

    Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If the PCM was substituted, and the symptom/indication goes away, replace the original PCM .

    NO 

    Repair an open in the FAN HI SIGNAL wire between the fan control relay and the PCM.

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