Engine-Codes - Mercedes-Benz - P0179 Mercedes-Benz

P0179 Mercedes-Benz Code - Fuel Composition Sensor Circuit High Input

- Code Popularity: 8,103 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P0179 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.
  • Flexible Fuel (FF) sensor to Vehicle Power (VPWR) circuit harness open or shorted
  • FF to VPWR circuit poor electrical connection
  • Open in FF sensor signal circuit
  • Short to ground in FF sensor signal circuit
  • Fuel contamination

Code Tech Notes

Replaced Fuel Composition Sensor

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How to Fix the DTC P0179 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 P0179 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.

What are Code Possible Symptoms?

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

What Does the P0179 Mercedes-Benz Code Mean?

Fuel Composition Sensors are used to determine the amount of ethanol alcohol in the gasoline. Normally, a gasoline engine should not have more than 10% ethanol alcohol in the fuel for proper operation. Some vehicles have a Flexible Fuel (FF) system on them that allow them to run on up to 85% ethanol alcohol in the fuel. The fuel composition sensor sends a frequency modulated signal to the engine controller which is proportional to the alcohol content of the fuel. The injector pulse width and the ignition timing are modified for the increased alcohol content. It takes almost twice the amount of alcohol compared to gasoline to produce the same power.

P0179 Mercedes-Benz Code - Fuel Composition Sensor Circuit High Input

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