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P0485 OBD-II Trouble Code: Cooling Fan Power/Ground Circuit Malfunction

Check Engine Light

Cooling Fan Power/Ground Circuit Malfunction

What the P0485 code means

The P0485 code indicates that your cooling fan power is malfunctioning in some way. This could mean that your fan is coming on when your engine is off, or that your fan is not coming on at all.

What causes the P0485 code?

There may be one or more causes for the P0485 code. One is a faulty cooling fan. Another is that your fan control relay harness is shorted or open. Your fan control relay or fan control circuit may also suffer from a poor electrical connection.

What are the symptoms of the P0485 code?

Your Check Engine light may come on to indicate that your car is having issues with its cooling fan functions. You may also see your service engine warning light coming on, or experience an overheating engine.

How does a mechanic diagnose the P0485 code?

A mechanic will look at your electric cooling fan to make sure it is running when it should and that your engine is not overheating. The electric cooling fan is controlled by the Engine Control Module (ECM) through the cooling fan relay and this is based on inputs from the intake air temperature (IAT) sensor, the engine coolant temperature (ECT) sensor, the A/C refrigerant pressure sensor, the A/C selector switch, and the vehicle speed sensor. Your mechanic will check all of these using his or her own diagnostic tools. He or she will make sure that the cooling fan relay comes on when the engine coolant temperature reaches 106°C or higher and when the vehicle is going less than 38 MPH. The cooling fan relay should come on regardless of speed when the engine coolant temperature is 151°C or higher and the A/C refrigerant pressure is high.

How serious is the P0485 code?

The P0485 code is very serious and, unless you are very skilled and have the proper tools, should be looked at by a professional technician. Please note that a P0485 demands your immediate attention, and that as soon as you discover that this might be your problem, you should have repairs.

What repairs can fix the P0485 code?

The main repair that will fix the P0485 code is replacing your cooling fan. To do this you first need to locate your car’s cooling fan. Next disconnect the power from the fan by finding the cable that runs from the engine to the fan and pull that cable free from the fan motor. Remove the hardware that keeps the cooling fan housing in place. Remove anything else that keeps you from removing the fan and its housing. Next, lift the car cooling fan and housing from the car, but make sure that you do this gently so you do not break the housing or any other components. Your next step is to place the unit on a flat surface, and then remove the fan blade from the shaft by releasing the screw or pin that holds it in place. Release the motor from the housing by removing the screws, and then attach the new motor to the housing. Now is the time to test your work. Turn on your vehicle and set the air conditioner to the maximum setting. How is your fan working?

Additional comments for consideration regarding the P0485 code

Car cooling fans are an essential component in the performance of your vehicle. You might be able to replace your fan by yourself, but you need to be patient and do the proper research in advance. But remember that it is always important to have the right diagnostic tools so that you know just what problems you are looking for and if you have located the correct problem or not. Do not be afraid to consult a professional, even if it is only to ask questions about doing the work yourself.

Need help with a P0485 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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