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DTC P0480

DTC P0480 Cooling fan relay NO. 1 control circuit problem
DETECTION CONDITION 
  • The PCM monitors the cooling fan relay NO. 1 control voltage when the PCM turns the cooling fan relay NO. 1 off. If the control voltage is low, the PCM determines that the cooling fan NO. 1 control circuit voltage is low.
  • The PCM monitors the cooling fan relay NO. 1 control voltage when the PCM turns the cooling fan relay NO. 1 on. If the control voltage is high, the PCM determines that the cooling fan NO. 1 control circuit voltage is high.

Diagnostic support note 
  • This is a continuous monitor (other).
  • The MIL does not illuminate.
  • PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
  • FREEZE FRAME DATA (Mode 2/Mode 12) is not available.
  • The DTC is stored in the PCM memory.
POSSIBLE CAUSE 
  • Cooling fan relay NO. 1 terminal malfunction
  • Short to ground or open circuit in cooling fan relay NO. 1 power supply circuit
    • Short to ground in wiring harness between main relay terminal C and cooling fan relay NO. 1 terminal A
    • Cooling fan relay NO. 1 related fuse malfunction
    • Open circuit in wiring harness between main relay terminal C and cooling fan relay NO. 1 terminal A
  • Short to ground in wiring harness between cooling fan relay NO. 1 terminal E and PCM terminal 1M
  • Cooling fan relay NO. 1 malfunction
  • PCM connector or terminals malfunction
  • Short to power supply in wiring harness between cooling fan relay NO. 1 terminal E and PCM terminal 1M
  • Open circuit in wiring harness between cooling fan relay NO. 1 terminal E and PCM terminal 1M
  • PCM malfunction
G07878121
DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY RELATED REPAIR INFORMATION AVAILABILITY 
  • Verify related Service Bulletins and/or on-line repair information availability.
  • Is any related repair information available?
 Yes Perform repair or diagnosis according to the available repair information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
2 INSPECT COOLING FAN RELAY NO. 1 CONNECTOR FOR POOR CONNECTION 
  • Turn the ignition switch off.
  • Remove the cooling fan relay NO. 1.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace the terminal, then go to Step 9.
No Go to the next step.
3 INSPECT COOLING FAN RELAY NO. 1 POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT 
  • Cooling fan relay NO. 1 is removed.
  • 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 the voltage B+? 
 Yes Go to the next step.
No Inspect the cooling fan relay NO. 1 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 CONTROL CIRCUIT FOR SHORT TO GROUND 
  • Cooling fan relay NO. 1 is removed.
  • Turn the ignition switch off.
  • Inspect for continuity between cooling fan relay NO. 1 terminal E (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:
Go to Step 9.
No Go to the next step.
5 INSPECT COOLING FAN RELAY NO. 1 
  • 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.
(See RELAY LOCATION ).
No Go to the next step.
6 INSPECT PCM CONNECTOR FOR POOR CONNECTION 
  • Turn the ignition switch oft.
  • Disconnect the PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace the connector and/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 
  • Coding 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 E (wiring harness-side) and body ground.
  • Is the voltage B+? 
 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 E (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.

    (See AFTER REPAIR PROCEDURE ).

  • Perform the KOEO or KOER self test.

    (See KOEO/KOER SELF TEST ).

  • Is the PENDING CODE same as 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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