Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Cooling Fan Control System Inspection
If simulation function of M-MDS is used:Β
- Connect the M-MDS to the DLC-2.
- Start the engine and warm it up to normal operating temperature.
- Verify that the DTC P0480, P0481 or P0482 is not shown and cooling fan operating while the KOER self-test.orm the KOER self-test. (See KOEO/KOER SELF TEST [LF] ).
- Verify that the DTC P0480, P0481 or P0482 is not shown and cooling fan operating while the KOER self-test.
- If the DTC P0480 is shown, perform the DTC troubleshooting procedure. (See DTC P0480 [LF] ). (See DTC P0481 [LF] ). (See DTC P0482 [LF] ).
- If the cooling fans do not operate while KOER self-test, proceed the followings:
- Inspect the cooling fan motor and wiring harness between cooling fan motor and ground.
- Select the FAN1, FAN2 and FAN3 PIDs.
- Turn ignition switch off and disconnect the cooling fan motor connector.
- Verify that each cooling fan relay operating sound is heard, when turn each cooing fan relay to on from off using simulation function of the FAN1, FAN2 and FAN3 PIDs.
- If the operation sound is not heard, inspect for suspected cooling fan relay is stuck open or close.
- If the operation sound is heard, inspect wiring harness and connector between all cooling fan relays and cooling fan motor.
If simulation function of M-MDS is not used:Β
- Connect the M-MDS to the DLC-2.
- Start the engine and warm it up to normal operating temperature.
- Perform the KOER self-test. (See KOEO/KOER SELF TEST [LF] ).
- Verify that the DTC P0480, P0481 or P0482 is not shown and cooling fan operating while the KOER self-test.
- If the DTC P0480 is shown, perform the DTC troubleshooting procedure. (See
DTC P0480 [LF]
). (See
DTC P0481 [LF]
).
(See DTC P0482 [LF] ).
- If the cooling fans do not operate while KOER self-test, proceed the followings:
- Inspect the cooling fan motor and wiring harness between cooling fan motor and ground.
- Turn the ignition switch to off.
- Disconnect ECT sensor connector.
- Verify that the operation sound heard form all cooling fan relays (No. 1, No. 2 and No. 3), when the ignition switch to ON position.
- If the operation sound is not heard, inspect for suspected cooling fan relay is stuck open or close.
- If the operation sound is heard, inspect wiring harness and connector between all cooling fan relays and cooling fan motor.
- Turn the ignition switch off and disconnect the ECT sensor connector.
- Reconnect the ECT sensor and clear the DTC from PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE [LF] ).
- If the DTC P0480 is shown, perform the DTC troubleshooting procedure. (See
DTC P0480 [LF]
). (See
DTC P0481 [LF]
).
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
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