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P0178 is a diagnostic trouble code (DTC) for "Fuel Composition Sensor Circuit Low Input". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
Fuel Composition Sensor Circuit Low Input
P0178 is a generic OBD-II code indicating that the diesel fuel sensor is giving a low input, which could be from an open circuit in the sensor or wiring
The engine control module (ECM) detects that the sensor circuit is open if the sensor input is below specifications
The ECM detects that the circuit is open if the wiring or connection to the sensor is not making a complete circuit, such as a connection that came loose, or wiring that got cut
Scans the codes and documents the freeze frame data, then clears the codes to verify code returns
Does a visual check of all the wiring and connections to the sensor, checking for breaks in the wiring or loose connections
Disconnects connection to sensor and checks to see if the sensor is testing within specifications
Follow these simple guidelines to prevent misdiagnosis:
Engine starting and running issues could occur if excessive water is in the fuel and the sensor cannot detect it
The engine may misfire, hesitate and stall
If there is no problems with the fuel then the only issue will be the check engine and water in fuel light will be on.
Not many manufactures use the code P0178. It is set in the computer memory to indicate that the engine fuel has, or had water in it. The code is only an indicator of water in the fuel and may be damaged by fuel additives added to the fuel.
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 1-800-701-6220.