Radiator Fan High Speed Circuit Troubleshooting

1. Check the No. 30 (30 A) fuse, and the No. 10 (7.5 A) fuse in the under-dash fuse/relay box.

   Are the fuses OK? 

   YES  -Go to step 2.

   NO  -Replace the fuse(s) and recheck. If the fuse(s) blow again, repair the short to ground in the No. 30 (30 A) fuse, and/or the No. 10 (7.5 A) fuse circuits.

2. Remove the radiator fan relay from auxiliary under-hood relay box, and the fan control relay from auxiliary under-hood fuse/relay box, and test them (see POWER RELAY TEST ).

   Are the relays OK? 

   YES  -Go to step 3.

   NO  -Replace the radiator fan relay and/or the fan control relay.

3. Check the radiator fan motor (see FAN MOTOR TEST ).

   Is the fan motor OK? 

   YES  -Go to step 4.

   NO  -Replace the radiator fan motor (see FAN, FAN MOTOR, AND SHROUD REMOVAL AND INSTALLATION ).

4. Measure the voltage between radiator fan relay 4P socket terminal No. 1 and body ground.
   Fig 1: Measuring Voltage Between Radiator Fan Relay 4P Socket Terminal No. 1 And Body Ground

   Courtesy of AMERICAN HONDA MOTOR CO., INC.

   Is there battery voltage? 

   YES  -Go to step 5.

   NO  -Repair an open in the wire between radiator fan relay 4P socket terminal No. 1 and the under-dash fuse/relay box.

5. Turn the ignition switch to ON (II).
6. Measure the voltage between radiator fan relay 4P socket terminal No. 4 and body ground.
   Fig 2: Measuring Voltage Between Radiator Fan Relay 4P Socket Terminal No. 4 And Body Ground

   Courtesy of AMERICAN HONDA MOTOR CO., INC.

   Is there battery voltage? 

   YES  -Go to step 7.

   NO  -Repair an open in the wire between radiator fan relay 4P socket terminal No. 4 and the under-dash fuse/relay box.

7. Measure the voltage between fan control relay 5P socket terminal No. 5 and body ground.
   Fig 3: Measuring Voltage Between Fan Control Relay 5P Socket Terminal No. 5 And Body Ground

   Courtesy of AMERICAN HONDA MOTOR CO., INC.

   Is there battery voltage? 

   YES  -Go to step 8.

   NO  -Repair an open in the wire between fan control relay 5P socket terminal No. 5 and the auxiliary under-hood relay box.

8. Turn the ignition switch to LOCK (0).
9. Disconnect the radiator fan motor 2P connector.
10. Check for continuity between radiator fan relay 4P socket terminal No. 2 and radiator fan motor 2P connector terminal No. 2.
    Fig 4: Checking Continuity Between Radiator Fan Relay 4P Socket Terminal No. 2 And Radiator Fan Motor 2P Connector Terminal No. 2.

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to the step 11.

    NO  -Repair an open in the wire between radiator fan relay 4P socket terminal No. 2 and radiator fan motor 2P connector terminal No. 2.

11. Check for continuity between fan control relay 5P socket terminal No. 1 and radiator fan motor 2P connector terminal No. 1.
    Fig 5: Checking Continuity Between Fan Control Relay 5P Socket Terminal No. 1 And Radiator Fan Motor 2P Connector Terminal No. 1

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to the step 12.

    NO  -Repair an open in the wire between fan control relay 5P socket terminal No. 1 and radiator fan motor 2P connector terminal No. 1.

12. Check for continuity between fan control relay 5P socket terminal No. 2 and body ground.
    Fig 6: Checking Continuity Between Fan Control Relay 5P Socket Terminal No. 2 And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to the step 13.

    NO  -Repair an open in the wire between fan control relay 5P socket terminal No. 2 and body ground G401.

13. Connect the HDS to the DLC (see step 2 on GENERAL TROUBLESHOOTING INFORMATION ).
14. Turn the ignition switch to ON (II).
15. Make sure the HDS communicates with the vehicle and the PCM. If it does not communicate, troubleshoot the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING ).
16. Jump the SCS line with the HDS, then turn the ignition switch to LOCK (0).
    NOTE: This step must be done to protect the PCM from damage.
17. Disconnect PCM connector A (49P).
18. Check for continuity between radiator fan relay 4P socket terminal No. 3 and PCM connector terminal No. A44.
    Fig 7: Checking Continuity Between Radiator Fan Relay 4P Socket Terminal No. 3 And PCM Connector Terminal No. A44

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to the step 19.

    NO  -Repair an open in the wire between radiator fan relay 4P socket terminal No. 3 and PCM connector terminal No. A44.

19. Check for continuity between fan control relay 5P socket terminal No. 3 and PCM connector terminal No. A45.
    Fig 8: Checking Continuity Between Fan Control Relay 5P Socket Terminal No. 3 And PCM Connector Terminal No. A45

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Update the PCM (see PCM UPDATE ) if it does not have the latest software, or substitute a know-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom goes away with a know-good PCM, replace the original PCM (see PCM REPLACEMENT ).

    NO  -Repair an open in the wire between fan control relay 5P socket terminal No. 3 and PCM connector terminal No. A45.

INTEGRATED MOTOR ASSIST (IMA) SYSTEM (If fuel and emissions maintenance is required) 

IMA components are located in this area. The IMA is a high-voltage system. The high voltage cables and their covers are identified by orange coloring. The safety labels are attached to high voltage and other related parts (see DANGER/WARNING/CAUTION LABEL LOCATIONS ). You must be familiar with the IMA system before working around it. Make sure you have read the Service Precautions in the IMA article before doing repairs or service (see SERVICE PRECAUTIONS ).