Loose, corroded or damaged connector at the fuel temperature sensor; Chafed, broken or intermittently shorting wiring between the sensor and ECU; Failing fuel temperature sensor with an internal intermittent fault; Poor ECU connector pin tension, moisture or corrosion in the ECU plug; Fault in the sensor reference voltage or ground supply shared with other sensors; Sensor integrated into the fuel pump, rail or filter housing failing, where the sensor is not sold separately (depends on model and engine); Internal ECU fault affecting the sensor input.

P0184

Fuel Temperature Sensor A Circuit Intermittent.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
84: FaultThe specific fault in that area

What it means

P0184 means the engine control unit has detected an intermittent fault in the fuel temperature sensor A circuit. The signal from the sensor drops out, spikes or jumps to implausible values from time to time instead of staying steady. The ECU uses this reading to correct fuel density and, on some engines, to adjust fuelling and injection timing.

Symptoms

Engine warning light on
Intermittent rough running or hesitation
Hard starting when hot or cold, sometimes only occasionally
Slightly higher fuel consumption
Fault appears and disappears, with the code sometimes clearing itself
Occasional poor performance or reduced power on some models

Possible causes

Loose, corroded or damaged connector at the fuel temperature sensorlikely
Chafed, broken or intermittently shorting wiring between the sensor and ECUlikely
Failing fuel temperature sensor with an internal intermittent faultlikely
Poor ECU connector pin tension, moisture or corrosion in the ECU plugpossible
Fault in the sensor reference voltage or ground supply shared with other sensorspossible
Sensor integrated into the fuel pump, rail or filter housing failing, where the sensor is not sold separately (depends on model and engine)possible
Internal ECU fault affecting the sensor inputrare

How to diagnose

Read all stored and pending codes and note the freeze frame data to see engine temperature and conditions when the fault set.
Check for related codes such as other sensor circuit faults, which could point to a shared reference or ground problem.
Locate the fuel temperature sensor for this model and engine, as its position varies, then inspect its connector and wiring for damage, rubbing, heat damage, fuel contamination or corrosion.
With the engine running, view live fuel temperature data and gently wiggle the connector and harness to see if the reading jumps or drops out.
Compare the live fuel temperature reading with the actual temperature of a cold engine, where it should be close to ambient and intake air temperature.
Check the sensor resistance against the manufacturer's specification at a known temperature.
Test the sensor reference voltage, signal and ground circuits for continuity, shorts and voltage drop using the wiring diagram.
Inspect the ECU connector for bent, pushed-back or corroded pins if the wiring and sensor test fine.

How to fix

Clean, refit or repair the sensor connector, and replace the terminals or connector if corroded or loose.
Repair or replace damaged sections of wiring, and secure the harness away from heat and abrasion.
Replace the fuel temperature sensor, or the assembly it is part of if it is not supplied separately.
Repair the shared reference voltage or ground fault if other sensors are also affected.
Repair ECU connector pin problems, and only consider ECU repair or replacement once all other causes are ruled out, following the manufacturer's procedure.

Can I keep driving?

Low severity

The car can normally be driven while you arrange a repair, as the fault is usually minor. If it starts to run badly, hesitate or struggle to start, get it checked sooner.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.