P0184 indicates that the Engine Control Module (ECM) has detected an intermittent electrical fault in the fuel temperature sensor circuit. The fuel temperature sensor (typically a thermistor located in the fuel tank or fuel rail) provides data used for fuel delivery calculations, fuel density compensation, and emissions control. When the ECM sees the sensor signal behave erratically—fluctuating between valid readings and open or short circuit conditions—it sets this code.
Internal sensor failures are the most common cause; the sensor's resistive element can degrade or the internal electrical connections can become intermittent.
Chafed, pinched, or broken wires in the sensor circuit—often from heat exposure, vibration, or rubbing against other components—can cause intermittent opens or shorts.
Moisture intrusion, oxidation, or loose harness connectors at the sensor or ECM can create intermittent high-resistance or open circuits.
An intermittent or poor ground connection for the sensor circuit can cause signal fluctuations that the ECM interprets as a circuit fault.
Rare, but the ECM itself can misinterpret sensor data or have internal circuit issues that trigger this code. This should be a diagnosis of exclusion after all wiring and sensor tests pass.
Generally yes, the vehicle will typically still run and drive. However, fuel delivery calculations may be slightly inaccurate, potentially causing minor fuel economy losses or driveability issues in extreme temperatures. The underlying intermittent fault could worsen over time, so timely diagnosis is recommended.
Probably not. PCM replacement is rarely needed for this code. The fuel temperature sensor, its wiring, and electrical connections are the cause in the vast majority of cases. ECM failure should only be considered after the sensor and wiring have been thoroughly tested and ruled out.
The fuel pump itself does not directly cause this code. However, the fuel temperature sensor is often integrated into the fuel pump module assembly in many vehicles, so replacing the pump module may resolve the sensor issue. Always verify which component houses the sensor for your specific vehicle.
Because P0184 is an intermittent code. The fault may only occur under specific conditions—certain temperatures, vibrations, or driving maneuvers—that the ECM cannot always replicate during a diagnostic visit. This makes catching the fault on a lift challenging and sometimes requires extended road testing with monitoring equipment.