P0483

What it means

P0483 means the engine control unit has run a rationality check on the cooling fan and the fan's behaviour did not match what it commanded. The ECU compares fan operation, typically via feedback signals, speed or current, or by looking at coolant temperature response, and found the result implausible. The exact test method varies by vehicle and engine.

Symptoms

• Engine cooling fan not running, or running constantly at full speed
• Engine temperature rising in traffic or when idling
• Air conditioning performing poorly or cutting out at idle
• Engine warning light on
• Temperature gauge reading higher than normal
• Possible reduced power if the ECU limits output to protect the engine

Possible causes

• Faulty cooling fan motor (worn, seized or drawing abnormal current)likely
• Damaged wiring, corroded or loose connectors in the fan power, ground or control circuitlikely
• Failed fan relay or blown fuselikely
• Faulty fan control module or fan speed controllerpossible
• Faulty coolant temperature sensor giving a misleading reading so the fan response looks wrongpossible
• Obstructed or damaged fan blades, shroud or debris restricting rotationpossible
• ECU fault or outdated calibration affecting the fan rationality test (model dependent)rare

How to diagnose

1. Read stored codes and freeze frame data, noting coolant temperature, vehicle speed and whether the air conditioning was on when the code set
2. Check for other related codes such as coolant temperature sensor or fan circuit faults and deal with those first
3. Visually inspect the fan, blades and shroud for damage, debris or stiffness, and check the fan spins freely by hand with the ignition off
4. Inspect the fuses, relay and the wiring and connectors to the fan and control module for heat damage, corrosion or chafing
5. Check coolant level and condition, and compare the coolant temperature sensor reading against a known accurate temperature measurement
6. Command the fan on with a scan tool and listen and watch for operation at each speed, where the vehicle supports it
7. Measure supply voltage, ground and control signal at the fan connector while commanding it, and check fan current draw against the manufacturer's specification
8. Test or swap the relay with a known good one, and follow model-specific procedures for testing the fan control module

How to fix

• Replace the cooling fan motor or fan assembly if it is seized, noisy or drawing incorrect current
• Repair damaged wiring or connectors and restore good power and earth connections
• Replace the faulty relay or blown fuse, and find out why the fuse blew
• Replace the fan control module if testing shows it is not responding correctly to commands
• Replace a faulty coolant temperature sensor
• Clear obstructions and repair or replace a damaged shroud, then clear the code and road test to confirm the fault does not return

Can I keep driving?

Nearby codes

• P0482GenericFan 3 Control Circuit
• P0484GenericFan Circuit Current High