Diagnostic Trouble Code (DTC): P0484
P0484 code definition
When the PCM detects a voltage reading from the electric cooling fan control circuit that is either too high or too low in comparison to the manufacturer’s specifications, the P0484 code will be stored.
What the P0484 code means
There are several components that send data to the ECM, allowing it to properly operate the electric cooling fan. This part ensures that the engine temperature does not get too high. If any of the components send data that is more than 10% higher or lower than the manufacturer’s specifications for the current driving conditions, the PCM will store the P0484 code to indicate that there is a malfunction within this circuit.
What causes the P0484 code?
The most common causes behind the P0484 code are a bad cooling fan motor, or a faulty cooling fan relay.
Other causes may include:
- Loose or corroded electrical components, such as wiring, harnesses, and connectors
- Faulty engine coolant temperature sensor
- Faulty cooling fan
If electrical components are shorted or open, there may also be blown fuses.
What are the symptoms of the P0484 code?
Most of the time, only the illuminated Check Engine Light will alert vehicle owners to the presence of the P0484 code; however, the engine may overheat, especially if this code has not been addressed in a timely manner. The air conditioner may also become less efficient at cooling the interior of the vehicle.
How does a mechanic diagnose the P0484 code?
After an OBD-II scanner detects the P0484 code, a technician should begin by inspecting all of the wiring and other electrical components. After repairing or replacing any components that were damaged, loose, corroded, or otherwise inoperable, it is important to clear the code from the PCM, and retest the system. If the code does not return, then the mechanic has diagnosed an electrical issue causing the P0484 code.
If the code does return, the next step is to perform a voltage and ground test on the cooling fan motor and cooling fan relay. Additionally, system fuses should be tested for proper voltage. If any of these parts give a reading that does not align with manufacturer specifications, then that part is likely to blame, and should be replaced.
The next step, should those parts not be faulty, is to diagnose the sensors that provide the ECM with the data necessary to operate the cooling fan. These include the intake air temperature sensor, the A/C refrigerant pressure sensor, the vehicle speed sensor, and the engine coolant temperature sensor. Throughout all diagnostic process, the code should be cleared and the system retested after each attempted repair. This process ensures that no unnecessary repairs are performed.
Common mistakes when diagnosing the P0484 code
Most often, technicians find that a cooling fan motor was replaced in error, when the cooling fan relay was actually to blame. Cooling fan relays are frequently recalled, so it’s important to consider both parts when performing diagnoses on the P0484 code.
How serious is the P0484 code?
If the P0484 code is being detected, the vehicle should be repaired right away. While no symptoms may be observed, an engine that cannot properly monitor engine temperature is likely to need more expensive repairs later on if the issue is not addressed early.
What repairs can fix the P0484 code?
In order to repair the P0484 code, the mechanic may attempt any of the following:
- Replace a bad cooling fan motor
- Replace a faulty cooling fan relay.
- Repair loose or corroded electrical components
- Replace a faulty engine coolant temperature sensor
- Replace a faulty cooling fan
Need help with a P0484 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.