P0184 - Fuel Temperature Sensor A Circuit Intermittent/Erratic
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P0184 is set when the Engine Control Module (ECM/PCM) detects an erratic or intermittent signal from the Fuel Temperature Sensor (FTS) 'A' circuit. The sensor is typically a NTC (Negative Temperature Coefficient) thermistor where resistance drops as temperature rises. The ECM monitors the voltage drop across the sensor; if the signal fluctuates rapidly or drops out in a way that is physically impossible given the thermal mass of the fuel, the code is triggered. This information is vital for adjusting fuel injector pulse width based on fuel density.
Possible Causes
Loose connection or corrosion in the sensor connector
Damaged wiring harness (chafed insulation or intermittent short)
Defective fuel temperature sensor (internal intermittent failure)
Faulty Engine Control Unit (ECU)
Symptoms
Recommended Solution
- 2. 3. Electrical Measurements: Verify 5V reference voltage from ECM with the sensor unplugged. 4. Component Replacement: If wiring and reference signals are within spec but the data remains erratic during operation, replace the fuel temperature sensor.
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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