P0482 OBD Error Code: Problem & Solutions

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P0482 is a diagnostic trouble code (DTC) for "Cooling Fan 3 Control Circuit Malfunction". It is a generic code applying to all OBD II (on board diagnostics) vehicles. This code indicates that the PCM (powertrain control module) has detected voltage in the cooling fan control circuit outside of the normal parameters. Voltage variations that vary by greater than 10-percent of the manufacturer’s specified reference voltage will cause a code to be stored and possibly a service engine soon lamp to be illuminated.

OBD Code P0482 is an indication of cooling fan 3 control circuit malfunction. Some vehicles have two or three cooling fans, and in this code the circuit involved is the one which operates fan 3. The P0482 code is detected when the Powertrain Control Module detects that the commanded state of the driver and the actual state of the control circuit do not match. PCM command the cooling fan relay to turn on the fan when it discovers that engine temperature reaches about 223-degrees F. It does so by supplying the ground to the relay. When the PCM attempts to activate the fan and senses the command and the result do not match, the code is set. This code should be rectified as soon as possible else can lead to serious issues in near future.

What causes this problem with the Cooling Fan 3 Control Circuit Malfunction?

• Inoperative cooling fan 3
• Damaged fan control relay 3
• Open or shorted cooling fan harness
• Frayed coolant temperature sensor
• Faulty electrical connections
• Defective VSS
• Faulty AC selector switch or refrigerant pressure sensor

1. Fan Control Relay - The typical electric cooling fan circuit includes a temperature sensor, a relay, a control module and the fan motor. The relay is the component that fails most often, so be sure to test the relay as well as its power supply and ground connections and replace the faulty one immediately.
2. Fan Control Relay Harness - Make sure the harness of fan control relay should not be defective or damaged. If you discover that faulty replace it.
3. Cooling Fan Motor - The cooling fan motor powers the cooling fans, in turn, keeping the engine from overheating. If it is frayed then obviously cause all the related trouble codes.
4. Engine Coolant Temperature Sensor - The engine coolant temperature (ECT) sensor is a relatively simple sensor that monitors the internal temperature of the engine. This is one of the crucial components so make sure it should work efficiently.
5. AC Selector Switch - Always replace the inoperative or damaged AC selector switch to avoid all the associated trouble codes.

Some common symptoms which help you identify the trouble code P0482 are listed below:

• Overheated engine
• AC may not work
• In some cases, cooling fan may stay on all the time
• Illuminated check engine light

We have listed some possible repairs and replacements that may help you to fix this trouble code P0482. Make sure any power steering leaks or other issues should be repaired before addressing the cooling fan fault. Possible repairs for this code may include:

• Broken, corroded or damaged wiring, connectors and other circuitry components should be replaced immediately
• Defective fan speed sensor should be replaced
• Replace the faulty cooling fan relay
• Inspect the fuses carefully and replace the faulty ones.

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Step by step diagnosis is required to address this trouble code by a experienced diagnostician as cooling fan circuitry consists of such a complex network of wires, connectors, relays, sensors, and other components, locating and repairing the problem can be a lengthy and complicated. Steps to diagnose this code are as follows:

• Visually inspect the fan and check if there is any hindrance in front of radiator blocking airflow.
• Check the electrical connection at the fan.
• Open the fuse block and inspect the cooling fan relay fuses.
• Look for the simple open and shut circuit.
• Jump the battery terminal to the fan harness terminal and the fan will operate.
• If the fan operated, check the relays.
• If the circuit has not closed or the relay has not clicked, the relay is bad.
• If there was no switched power at the relay, the ignition switch is suspect.
• Shut the engine down and pull the CTS plug again. Check it with the ohmmeter, there should be a big change in resistance, if not the sensor is bad.
• If the above procedure could not find a failure, the probability is that a poor connection to the PCM or the PCM itself is at fault.

Common Mistakes When Diagnosing the P0482 Code

Do not skip the steps while diagnosing the code as it can lead to some common mistakes. Always check the components carefully and thoroughly to avoid unnecessary replacements. In this code usually, people replace cooling fan motor without doing a thorough analysis.