DTC P0481


DTC P0481	Cooling fan No.2 control circuit problem
DETECTION CONDITION	• The PCM monitors the cooling fan relay No.2 control voltage when the PCM turns the cooling fan relay No.2 off. If the control voltage is low, the PCM determines that the cooling fan No.2 control circuit voltage is low. • The PCM monitors the cooling fan relay No.2 control voltage when the PCM turns the cooling fan relay No.2 on. If the control voltage is high, the PCM determines that the cooling fan No.2 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 is available. • The DTC is stored in the PCM memory.
POSSIBLE CAUSE	• Cooling fan relay No.2/No.3 malfunction • Connector or terminal malfunction • Open circuit in wiring harness between main relay terminal C and cooling fan relay No.2 terminal A • Short to GND in wiring harness between main relay terminal C and cooling fan relay No.2 terminal A • Open circuit in wiring harness between main relay terminal C and cooling fan relay No.3 terminal A • Short to GND in wiring harness between main relay terminal C and cooling fan relay No.3 terminal A • Open circuit in wiring harness between cooling fan relay No.2 terminal E and PCM terminal 5AD • Short to power supply in wiring harness between cooling fan relay No.2 terminal E and PCM terminal 5AD • Short to GND in wiring harness between cooling fan relay No.2 terminal E and PCM terminal 5AD • Open circuit in wiring harness between cooling fan relay No.3 terminal E and PCM terminal 5AD • Short to power supply in wiring harness between cooling fan relay No.3 terminal E and PCM terminal 5AD • Short to GND in wiring harness between cooling fan relay No.3 terminal E and PCM terminal 5AD • PCM malfunction


STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related service 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.
2		No	Go to the next step.
3	INSPECT COOLING FAN RELAY NO.2/NO.3 CONNECTOR FOR POOR CONNECTION • Turn the ignition switch off. • Disconnect the cooling fan relay No.2/No.3 connector. • 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 10.
3		No	Go to the next step.
4	INSPECT COOLING FAN RELAY NO.2/NO.3 POWER CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GND • Turn the ignition switch to the ON position (Engine off). • Measure the voltage between the following circuits: – Cooling fan relay No.2 terminal A (wiring harness-side) and body GND – Cooling fan relay No.3 terminal A (wiring harness-side) and body GND • Is the voltage B+?	Yes	Go to the next step.
4		No	Repair or replace the wiring harness for a possible open circuit or short to GND, then go to Step 10.
5	INSPECT COOLING FAN RELAY NO.2/NO.3 CONTROL CIRCUIT FOR SHORT TO GND • Turn the ignition switch off. • Inspect for continuity between the following circuits: – Cooling fan relay No.2 terminal E (wiring harness-side) and body GND – Cooling fan relay No.3 terminal E (wiring harness-side) and body GND • Is there continuity?	Yes	Repair or replace the wiring harness for a possible short to GND, then go to Step 10.
5		No	Go to the next step.
6	INSPECT COOLING FAN RELAY NO.2/NO.3 CONTROL CIRCUIT FOR SHORT TO POWER SUPPLY • Turn the ignition switch to the ON position (Engine off). • Measure the voltage between the following circuits: – Cooling fan relay No.2 terminal E (wiring harness-side) and body GND – Cooling fan relay No.3 terminal E (wiring harness-side) and body GND • Is the voltage B+?	Yes	Repair or replace the wiring harness for a possible short to power supply, then go to Step 10.
6		No	Go to the next step.
7	INSPECT COOLING FAN RELAY NO.2/NO.3 • Inspect the cooling fan relay No.2/No.3. (See RELAY INSPECTION.) • Is there any malfunction?	Yes	Replace the cooling fan relay No.2/No.3, then go to Step 10. (See RELAY LOCATION.)
7		No	Go to the next step.
8	INSPECT PCM CONNECTOR FOR POOR CONNECTION • Turn the ignition switch off. • Disconnect the PCM connector. • 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 10.
8		No	Go to the next step.
9	INSPECT COOLING FAN RELAY NO.2/NO.3 CONTROL CIRCUIT FOR OPEN CIRCUIT • Turn the ignition switch off. • Inspect for continuity between the following circuits: – Cooling fan relay No.2 terminal E (wiring harness-side) and PCM terminal 5AD (wiring harness-side) – Cooling fan relay No.3 terminal E (wiring harness-side) and PCM terminal 5AD (wiring harness-side) • Is there continuity?	Yes	Go to the next step.
9		No	Repair or replace the wiring harness for a possible open circuit, then go to the next step.
10	VERIFY TROUBLESHOOTING OF DTC P0481 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the WDS or equivalent. • Start the engine. • Is the PENDING CODE same as DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION.)
10		No	Go to the next step.
11	VERIFY AFTER REPAIR PROCEDURE • Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE.) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE.)
11		No	DTC troubleshooting completed.