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DTC P0480

DTC P0480  Cooling fan relay No. 1 control circuit malfunction 
DETECTION CONDITION 
  • The PCM monitors the cooling fan relay No. 1 control signal voltage and current. If the following conditions are met, the PCM determines that there is the cooling fan relay No. 1 control circuit problem.
    • The PCM turns the cooling fan relay No. 1 off, but the voltage of the cooling fan relay No. 1 control signal remains low.
    • The PCM turns the cooling fan relay No. 1 on, but the current of the cooling fan relay No. 1 control signal remains high.

Diagnostic support note 
  • This is a continuous monitor (other).
  • The MIL does not illuminate.
  • FREEZE FRAME DATA (Mode 2/Mode 12) is available.
  • The DTC is stored in the PCM memory.
POSSIBLE CAUSE 
  • Open circuit or short to ground in cooling fan relay No. 1 power supply circuit
    • Short to ground in wiring harness between battery positive terminal and cooling fan relay No. 1 terminal E
    • Cooling fan relay No. 1 power supply circuit related fuse malfunction
    • Open circuit in wiring harness between battery positive terminal and cooling fan relay No. 1 terminal E
  • Cooling fan relay No. 1 malfunction
  • Short to ground in wiring harness between cooling fan relay No. 1 terminal A and PCM terminal 1M
  • PCM connector or terminals malfunction
  • Short to power supply in wiring harness between cooling fan relay No. 1 terminal A and PCM terminal 1M
  • Open circuit in wiring harness between cooling fan relay No. 1 terminal A and PCM terminal 1M
  • PCM malfunction
G07877633
DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA (MODE 12) AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED 
  • Have the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS (other related) been recorded?
 Yes Go to the next step.
No Record the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2 VERIFY RELATED SERVICE BULLETINS AVAILABILITY 
  • Verify related Service Bulletins availability.
  • Is any related Service Bulletins available?
 Yes Perform the repair or diagnosis according to the available Service Bulletins.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 INSPECT COOLING FAN RELAY NO. 1 POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND 
  • Turn the ignition switch off.
  • Remove the cooling fan relay No. 1.
  • Turn the ignition switch to the ON position (Engine off).
  • Measure the voltage between cooling fan relay No. 1 terminal E (wiring harness-side) and body ground.
  • Is the voltage B  ?
 Yes Go to the next step.
No Inspect the cooling fan relay No. 1 power supply circuit related fuse.
  • If the fuse is melt:
    • Repair or replace the wiring harness for a possible short to ground.
    • Replace the fuse.
  • If the fuse is deterioration:
    • Replace the fuse.
  • If the fuse is normal:
    • Repair or replace the wiring harness for a possible open circuit

Go to Step 9.
4 INSPECT COOLING FAN RELAY NO. 1 
  • Turn the ignition switch off.
  • Inspect the cooling fan relay No. 1.

    (See RELAY INSPECTION ).

  • Is there any malfunction?
 Yes Replace the cooling fan relay No. 1, then go to Step 9.
No Go to the next step.
5 INSPECT COOLING FAN RELAY NO. 1 CONTROL CIRCUIT FOR SHORT TO GROUND 
  • Cooling fan relay No. 1 is removed.
  • Inspect for continuity between cooling fan relay No. 1 terminal A (wiring harness-side) and body ground.
  • Is there continuity?
 Yes If the short to ground circuit could be detected:
  • Repair or replace the wiring harness for a possible short to ground.

    If the short to ground circuit could not be detected:

  • Replace the PCM (short to ground in PCM internal circuit).

    (See PCM REMOVAL/INSTALLATION ).


Go to Step 9.
No Go to the next step.
6 INSPECT PCM CONNECTOR AND TERMINALS 
  • Disconnect the PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, and corrosion).
  • Is there any malfunction?
 Yes Repair or replace the connector or terminals, then go to Step 9.
No Go to the next step.
7 INSPECT COOLING FAN RELAY NO. 1 CONTROL CIRCUIT FOR SHORT TO POWER SUPPLY 
  • Cooling fan relay No. 1 is removed and PCM connector is disconnected.
  • Turn the ignition switch to the ON position (Engine off).
  • Measure the voltage between cooling fan relay No. 1 terminal A (wiring harness-side) and body ground.
  • Is there any voltage?
 Yes Repair or replace the wiring harness for a possible short to power supply, then go to Step 9.
No Go to the next step.
8 INSPECT COOLING FAN RELAY NO. 1 CONTROL CIRCUIT FOR OPEN CIRCUIT 
  • Cooling fan relay No. 1 is removed and PCM connector is disconnected.
  • Turn the ignition switch off.
  • Inspect for continuity between cooling fan relay No. 1 terminal A (wiring harness-side) and PCM terminal 1M (wiring harness-side).
  • Is there continuity?
 Yes Go to the next step.
No Repair or replace the wiring harness for a possible open circuit, then go to the next step.
9 VERIFY TROUBLESHOOTING OF DTC P0480 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the M-MDS.
  • Perform the KOEO or KOER self test with M-MDS, or following procedures:

    (See KOEO/KOER SELF TEST ).

    • Access the ECT PID.
    • Start the engine and warm up it until the ECT PID above 100°C {212°F}. 
    • Retrieve any DTC.
  • Is the same DTC present?
 Yes Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION ).
No Go to the next step.
10 VERIFY AFTER REPAIR PROCEDURE 
 Yes Go to the applicable DTC inspection.
(See DTC TABLE ).
No DTC troubleshooting completed.
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