DTC Troubleshooting

DTC Troubleshooting: P0480

DTC P0480: RFC System Malfunction

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Reading and Clearing Diagnostic Trouble Codes

1. Turn the ignition switch to ON (II).

2. Clear the DTC with the HDS, and wait 3 minutes or more.

3. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0480 indicated?
YES - Go to step 6.

NO - Go to step 4.


4. Select RADIATOR FAN in the INSPECTION MENU with the HDS.

5. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0480 indicated?
YES - Go to step 6.

NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the RFC unit, the RFC unit relay, the radiator fan motor, the condenser fan motor, and the PCM.


6. Check for these conditions at the radiator fan and the condenser fan:
- Interference with fan shroud

- Debris in the fan

- Ice on the fan blades

Are both fans OK?
YES - Go to step 7.

NO - Repair or replace the damaged parts, then go to step 52.


7. Select RADIATOR FAN in the INSPECTION MENU with the HDS.

8. Check the radiator fan and the condenser fan operation.

Do both fans operate?
YES - Go to step 9.

NO - Replace the motor that is not operating, then go to step 52.


9. Turn the ignition switch to LOCK (0).

10. Let the engine cool until the coolant temperature is low.

11. Turn the ignition switch to ON (II), and wait 3 minutes or more.

12. Confirm that the A/C is not switched on.

13. Check the radiator fan and the condenser fan operation.

Do both fans keep running?
YES - Go to step 25.

NO - Go to step 14.


14. Turn the ignition switch to LOCK (0).

15. Check the No. 23 IGP (7.5 A) fuse in the driver's under-dash fuse/relay box.

Is the fuse OK?
YES - Go to step 16.

NO - Repair short in the wire between the RFC unit relay and the No. 23 IGP (7.5 A) fuse. Also replace the No. 23 IGP (7.5 A) fuse, then go to step 52.


16. Check the No. 34 +B RAD FAN (50 A) fuse in the battery terminal fuse box.

Is the fuse OK?
YES - Go to step 17.

NO - Go to step 31.


17. Disconnect the RFC unit 1P connector.

18. Turn the ignition switch to ON (II), and wait 3 minutes or more.

19. Measure the voltage between the RFC unit 1P connector terminal and body ground.

Is there battery voltage?
YES - Go to step 20.

NO - Go to step 39.






20. Turn the ignition switch to LOCK (0).

21. Check for continuity between PCM connector terminal E6 and body ground.

Is there continuity?
YES - Go to step 22.

NO - Substitute a known-good RFC unit, RFC Unit Replacement then go to step 52 and recheck. If DTC P0480 is not indicated, replace the original RFC unit, RFC Unit Replacement then go to step 52.






22. Jump the SCS line with the HDS.

23. Disconnect PCM connector E (31P).

24. Check for continuity between PCM connector terminal E6 and body ground.

Is there continuity?
YES - Repair short in the wire between the PCM (E6) and the RFC unit, then go to step 52.

NO - Go to step 58.






25. Measure the voltage between PCM connector terminal E6 and body ground.

Is there about 5 V?
YES - Go to step 58.

NO - Go to step 26.






26. Jump the SCS line with the HDS.

27. Disconnect PCM connector E (31P).

28. Disconnect the RFC unit 3P connector.

29. Connect RFC unit 3P connector terminal No. 1 and body ground with a jumper wire.






30. Check for continuity between PCM connector terminal E6 and body ground.

Is there continuity?
YES - Substitute a known-good RFC unit, RFC Unit Replacement then go to step 52 and recheck. If DTC P0480 is not indicated, replace the original RFC unit, RFC Unit Replacement then go to step 52.

NO - Repair open in the wire between the PCM (E6) and the RFC unit, then go to step 52.






31. Remove the air cleaner, Service and Repair and remove the RFC unit relay (A).






32. Check for continuity between RFC unit relay 4P connector terminal No. 1 and body ground.

Is there continuity?
YES - Repair short in the wire between the RFC unit relay and the No. 34 +B RAD FAN (50 A) fuse. Also replace the No. 34 +B RAD FAN (50 A) fuse, then go to step 52.

NO - Go to step 33.






33. Disconnect the RFC unit 1P connector.

34. Check for continuity between the RFC unit 1P connector terminal and body ground.

Is there continuity?
YES - Repair short in the wire between the RFC unit relay (+B line) and the RFC unit. Also replace the No. 34 +B RAD FAN (50 A) fuse, then go to step 52.

NO - Go to step 35.






35. Disconnect the RFC unit 2P connector (connected to radiator fan motor).

36. Check for continuity RFC unit 2P connector terminal No. 1 and body ground.

Is there continuity?
YES - Repair short in the wire between the RFC unit and the radiator fan motor. Also replace the No. 34 +B RAD FAN (50 A) fuse, then go to step 52.

NO - Go to step 37.






37. Disconnect the RFC unit 2P connector (connected to the A/C condenser fan motor).

38. Check for continuity between RFC unit 2P connector terminal No. 1 and body ground.

Is there continuity?
YES - Repair short in the wire between the RFC unit and the condenser fan motor. Also replace the No. 34 +B RAD FAN (50 A) fuse, then go to step 52.

NO - Substitute a known-good RFC unit, RFC Unit Replacement then go to step 52 and recheck. If DTC P0480 is not indicated, replace the original RFC unit, RFC Unit Replacement then go to step 52.






39. Turn the ignition switch to LOCK (0).

40. Remove the air cleaner, Service and Repair and remove the RFC unit relay (A).

41. Check the RFC unit relay. Power Relay Test

Is the RFC unit relay OK?
YES - Go to step 42.

NO - Replace the RFC unit relay, then go to step 52.






42. Turn the ignition switch to ON (II).

43. Measure the voltage between RFC unit relay 4P connector terminal No. 1 and body ground.

Is there battery voltage?
YES - Go to step 44.

NO - Repair open in the wire between the RFC unit relay and the No. 34 +B RAD FAN (50 A) fuse, then go to step 52.






44. Measure the voltage between RFC unit relay 4P connector terminal No. 4 and body ground.

Is there battery voltage?
YES - Go to step 45.

NO - Repair open in the wire between the RFC unit relay and the No. 23 IGP (7.5 A) fuse, then go to step 52.






45. Connect RFC unit relay 4P connector terminal No. 2 and body ground with a jumper wire.






46. Check for continuity between the RFC unit 1P connector terminal and body ground.

Is there continuity?
YES - Go to step 47.

NO - Repair open in the wire between the RFC unit relay (+B line) and the RFC unit, then go to step 52.






47. Remove the jumper wire from the RFC unit relay 4P connector.

48. Jump the SCS line with the HDS.

49. Disconnect PCM connector A (31P).

50. Connect RFC unit relay 4P connector terminal No. 3 and body ground with a jumper wire.






51. Check for continuity between PCM connector terminal A13 and body ground.

Is there continuity?
YES - Go to step 58.

NO - Repair open in the wire between the PCM (A13) and the RFC unit relay, then go to step 52.






52. Turn the ignition switch to LOCK (0).

53. Reconnect all connectors.

54. Turn the ignition switch to ON (II).

55. Reset the PCM with the HDS.

56. Do the PCM idle learn procedure. PCM Idle Learn Procedure

57. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0480 indicated?
YES - Check for poor connections or loose terminals at the RFC unit, the RFC unit relay, the radiator fan motor, the condenser fan motor, and the PCM.

NO - Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.


58. Reconnect all connectors.

59. Update the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM. Reading and Clearing Diagnostic Trouble Codes

60. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0480 indicated?
YES - Check for poor connections or loose terminals at the RFC unit, the RFC unit relay, the radiator fan motor, the condenser fan motor, and the PCM. If the PCM was updated, substitute a known-good PCM, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1.

NO - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. Service and Repair If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.