P0180 OBD-II Trouble Code: Fuel Temperature Sensor A Circuit Malfunction

Fuel Temperature Sensor ‘A’ Circuit Malfunction

What the P0180 code means

P0180 is a generic OBD-II code that is triggered by a malfunctioning fuel temperature sensor 'A.' This could indicate that the sensor is not within specification, or that the fuel temperature or fuel rail is too hot or too cold.

What causes the P0180 code?

• The engine control module (ECM) sets the P0180 code to memory when it detects a malfunctioning sensor circuit; the sensor input is either below or above the specified range designed for the sensor

• The fuel could be too hot or too cold

• The fuel tank or fuel rail temperature sensor could be out of sensor range, or the connector could be corroded

• In diesel engines, the ECM monitors the temperature of the diesel fuel when the fuel heater is activated, and will set the P0180 code if the temperature is out of range

What are the symptoms of the P0180 code?

• The vehicle will not start if the fuel is frozen from extreme cold, or if there is water in the fuel

• The vehicle will not start, or may lose power and stall, if the fuel gets too hot and boils off

• Excessive additives in the fuel can cause erratic sensor readings and cause the fuel to boil off at lower temperatures, causing the sensor to malfunction

How does a mechanic diagnose the P0180 code?

• Scans 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 the connection to the sensor and checks to see if the sensor is testing within specifications

• Takes a fuel sample to compare the actual temperature of fuel to the sensor input

• Tests the diesel fuel heater for proper operation to make sure it is working to heat the fuel, without overheating the fuel

Common mistakes when diagnosing the P0180 code

Follow these simple guidelines to prevent misdiagnosis:

• Do a visual check of the connections to the sensor to make sure they are making good contact with the fuel heater and fuel temperature sensor

• Check the fuel for excessive additives that can cause sensors to malfunction

How serious is the P0180 code?

• The vehicle will not start if excessive water is in the fuel, the ambient temperature is below freezing, and the fuel heater is defective due to the temperature sensor

• The engine may misfire, hesitate, and stall if the fuel temperature exceeds normal operating temperatures due to temperature sensor circuit malfunction, or if the fuel rail gets too hot.

What repairs can fix the P0180 code?

• Testing the fuel temperature sensor and replacing it if it is out of specifications
• Repairing or replacing a defective connector or wiring to the sensor
• Replacing the diesel fuel heater assembly with the temperature sensor

Additional comments for consideration regarding the P0180 code

The code P0180 is used on diesel engines with fuel heaters and on gasoline engines to monitor the fuel temperature in the fuel tank or at the fuel rail. Follow the manufacturer's recommended testing procedures for the vehicle and type of fuel you are working on.

Need help with a P0180 code?

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