P0179 Chevrolet Code - Fuel Composition Sensor Circuit High Frequency
Quick Answer
The Fuel Composition Sensor (FCS), or Flex Fuel Sensor (service parts term), measures the ethanol-gasoline ratio of the fuel being used in a flexible fuel vehicle. Common causes include Faulty Fuel Composition Sensor (FCS) or Flex Fuel Sensor, Fuel Composition Sensor harness is open or shorted, Fuel Composition Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0179 Chevrolet indicates Fuel Composition Sensor Circuit High Frequency.
- Common causes
- Common causes include Faulty Fuel Composition Sensor (FCS) or Flex Fuel Sensor, Fuel Composition Sensor harness is open or shorted, Fuel Composition Sensor circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0179 Chevrolet Description
Alcohol content information is supplied to the Engine Control Module (ECM) from the Fuel Composition Sensor. The Fuel Composition Sensor has an ignition positive circuit, a signal circuit, and a ground circuit. The Fuel Composition Sensor uses a microprocessor inside the sensor to measure the ethanol percentage and changes the output signal accordingly. The signal circuit carries the ethanol percentage via the frequency signal. The ECM provides an internal pull up to 5V on the signal circuit, and the fuel composition sensor pulls the 5V to ground in pulses. The normal range of operating frequency is between 50 - 150 Hz. The microprocessor inside the sensor is capable of a certain amount of self-diagnosis. An output frequency between 180 Hz and 190 Hz indicates that the fuel is contaminated. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the fuel composition sensor output frequency is less than 45 Hz for greater than 6s.
What are the Possible Causes of the DTC P0179 Chevrolet?
- Faulty Fuel Composition Sensor (FCS) or Flex Fuel Sensor
- Fuel Composition Sensor harness is open or shorted
- Fuel Composition Sensor circuit poor electrical connection
- Faulty Engine Control Module (ECM)
How to Fix the DTC P0179 Chevrolet?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
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What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0179 Chevrolet code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific Chevrolet Models
- P0179 2014 Chevrolet Silverado — Fuel Composition Sensor Circuit High Frequency
- P0179 2015 Chevrolet Silverado — Fuel Composition Sensor Circuit High Frequency
- P0179 2016 Chevrolet Silverado — Fuel Composition Sensor Circuit High Frequency
- P0179 2017 Chevrolet Silverado — Fuel Composition Sensor Circuit High Frequency
- P0179 2018 Chevrolet Silverado — Fuel Composition Sensor Circuit High Frequency
Frequently Asked Questions about P0179 Chevrolet Code
1. What does the OBDII code P0179 mean for a Chevrolet?
The code P0179 indicates that the fuel composition sensor circuit is detecting a frequency that is higher than expected.
2. What are the symptoms of P0179 on a Chevrolet?
Common symptoms include poor fuel economy, rough idling, reduced engine performance, and possibly an illuminated check engine light.
3. What causes the P0179 code to appear on a Chevrolet?
Possible causes include a faulty fuel composition sensor, damaged wiring or connectors, or issues with the ECM misinterpreting the sensor signal.
4. Can I drive my Chevrolet with the P0179 code?
While driving may be possible, it is not recommended as the issue can lead to reduced performance and potential damage to the engine over time.
5. How do I diagnose the P0179 code on a Chevrolet?
Diagnose the issue by inspecting the fuel composition sensor, wiring, and connectors for damage or corrosion, and using a multimeter to check for proper voltage signals.
6. How can I fix the P0179 code on a Chevrolet?
Repairs may include replacing the fuel composition sensor, repairing or replacing damaged wiring, and clearing the code with an OBDII scanner after fixing the issue.
7. Is the fuel composition sensor expensive to replace on a Chevrolet?
The cost varies depending on the model, but typically ranges from $150 to $400 for parts and labor.
8. Can a dirty fuel system cause the P0179 code on a Chevrolet?
While uncommon, contamination in the fuel system could potentially affect the fuel composition sensor’s readings.
9. Does the P0179 code affect ethanol or flex-fuel vehicles more frequently?
Yes, this code often appears on flex-fuel vehicles because the fuel composition sensor monitors ethanol content in the fuel.
10. Will resetting the check engine light clear the P0179 code on a Chevrolet?
No, resetting the light without addressing the underlying issue will only temporarily clear the code, and it will likely return.
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