Engine-Codes - Mercedes-Benz - P0485 Mercedes-Benz

P0485 Mercedes-Benz Code - Cooling Fan Power/Ground Circuit Malfunction

- Code Popularity: 8,249 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P0485 Mercedes-Benz?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty fan control relay
  • Faulty cooling fan
  • Fan control relay harness is open or shorted
  • Fan control relay circuit poor electrical connection
  • Fan cooling fan harness is open or shorted
  • Fan cooling fan circuit poor electrical connection
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How to Fix the DTC P0485 Mercedes-Benz?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0485 Mercedes-Benz code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

When is the Code Detected?

The P0485 code is detected when the Powertrain Control Module (PCM) detects that the commanded state of the driver and the actual state of the control circuit do not match.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Engine overheating

What Does the P0485 Mercedes-Benz Code Mean?

The electric cooling fan is controlled by the Engine Control Module (ECM) through the cooling fan relay based on inputs from the following components:
- The engine coolant temperature (ECT) sensor
- The intake air temperature (IAT) sensor
- The A/C selector switch
- The A/C refrigerant pressure sensor
- The vehicle speed sensor (VSS)
The ECM controls the cooling fan by grounding the cooling fan control circuit which turns ON the cooling fan relay. The cooling fan relay will be commanded ON when the following conditions are met:
- The engine coolant temperature reaches 106°C (223°F) or more.
- The A/C clutch requested.
- The vehicle speed is less than 38 MPH.
The cooling fan relay will be commanded ON regardless of vehicle speed when the following conditions are met:
- The engine coolant temperature is 151°C (304°F) or more.
- The A/C refrigerant pressure is high.
The cooling fan may be commanded ON when the engine is not running under a fan run-on conditions described in the electric cooling fan general description portion of the service manual.

P0485 Mercedes-Benz Code - Cooling Fan Power/Ground Circuit Malfunction

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