Skip the auto shop - Our mechanics make house calls

P0177 OBD-II Trouble Code: Fuel Composition Sensor Circuit Range/Performance

Check Engine Light

P0177 code definition

Fuel Composition Sensor Circuit Range/Performance

What the P0177 code means

P0177 is a generic OBD-II code indicating that the diesel fuel sensor has detected water in the fuel filter, or the fuel composition sensor is out of its specification range.

What causes the P0177 code?

  • The engine control module (ECM) receives input from the diesel fuel sensor that water is detected in the fuel, or the fuel composition sensor is not within specification range, and triggers the P0177 code

What are the symptoms of the P0177 code?

  • The Water in Fuel illuminates on the instrument cluster
  • The ECM sets code P0177 to memory and triggers the Check Engine Light

How does a mechanic diagnose the P0177 code?

  • Scans codes and documents the freeze frame data, then clears the codes to verify code returns

  • Drains off water in the fuel filter by opening the water drain valve on the fuel filter housing

  • If the Water in the Fuel Light does not go out, removes the fuel filter and tests the sensor, replacing it if shorted or out of specification range for the vehicle being tested

  • Clears codes and tests the system to see if the Water in Fuel Light goes out, and the P0177 code does not return

Common mistakes when diagnosing the P0177 code

Follow these simple guidelines to prevent misdiagnosis:

  • Drain fuel from the filter until no more water is present. If excess water is still in the fuel sample, then the fuel in the tank may be contaminated with excessive water and would need to be drained and replaced.

How serious is the P0177 code?

  • If excessive water is in the fuel then you will have engine starting and running issues.
  • The engine may misfire, hesitate, and stall.

What repairs can fix the P0177 code?

Additional comments for consideration regarding the P0177 code

Not many manufactures use the code P0177, and the code is set in the computer memory to indicate the engine fuel has or had water in it.

Need help with a P0177 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Find the Keyless Code on a Ford Explorer or Mercury Mountaineer
Many Ford Explorers and Mercury Mountaineers were manufactured with an option known as the Ford keyless entry keypad. Some models refer to it as SecuriCode as well. It...
Veteran and Military Driver Laws and Benefits in Idaho
The state of Idaho offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...


Related questions

Q: P0446 trouble code

Hi there, thanks for writing in. This P0446 trouble code relates to the evaporation control system circuit, which is a restricted vent path for the EVAP (Emergency Vehicle Accident Prevention) system. There is a solenoid in this circuit that sometimes...

Q: I need to know what the trouble code P19DA means

Hi there. The code P19DA means that the fuel pump is not sending a signal back to the PCM. This is usually caused by a burned motor in the fuel pump or a burned meter wire in the fuel pump...

Q: transmission shifting

If you are still getting the P0720 code after replacing the sensor then you should verify the wiring connection first to the sensor and also in between the sensor and ECM. Remove the sensor and turn the drive shaft. From...