P0184
Fuel Temperature Sensor A Circuit IntermittentP0184 is a generic OBD-II powertrain diagnostic trouble code: Fuel Temperature Sensor A Circuit Intermittent. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0184 means
P0184 is logged when the PCM detects an erratic or intermittent signal from fuel temperature sensor "A" rather than a sustained out-of-range reading. The PCM monitors the rate of change of the sensor's output; when it detects a temperature swing exceeding approximately ±10 °C (±18 °F) within 100 milliseconds — a change that is physically impossible given the thermal mass of the fuel — it classifies the fault as intermittent and stores P0184. Because the fault comes and goes, it is often the most difficult of the fuel temperature sensor codes to reproduce and trace. Common root causes are mechanically loose connectors, micro-fractures in the wiring harness that open and close with vibration or heat cycling, or a sensor whose thermistor element is beginning to fail internally. The MIL will illuminate after the fault threshold is exceeded a defined number of times within a drive cycle. Fuel economy, starting behaviour, and emissions are affected in the same way as P0180 when the signal dropout occurs, but the PCM may self-recover between events, making drivability symptoms come and go unpredictably.
Common causes
Most-frequently reported root causes when P0184 is logged.
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1
Loose or intermittently contacting connector pins at the sensor or PCM harness end
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2
Micro-fractures or chafe points in the wiring harness that open under vibration or thermal cycling
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3
Corroded connector terminals causing high-resistance contacts that drop in and out
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4
Failing fuel temperature sensor with an internally cracking thermistor element
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5
Water or moisture ingress at a connector that evaporates and returns seasonally
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6
Damaged wiring routed too close to hot or moving engine components causing intermittent shorts
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7
Faulty PCM input circuit with marginal signal conditioning (rare)
Symptoms drivers notice
How to diagnose P0184
A typical diagnostic flow when this code is present.
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1
Retrieve and document all stored and pending fault codes; note freeze-frame data to understand the conditions under which the fault was recorded
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2
Perform a thorough visual inspection of the sensor connector and full harness run for loose terminals, chafing, heat damage, or signs of moisture ingress
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3
With the engine running, monitor the fuel temperature sensor PID on a live scan tool while firmly wiggling and flexing each section of the wiring harness; an instantaneous dropout or spike confirms a harness fault location
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4
Disconnect and re-seat all connectors in the circuit, cleaning terminals with electrical contact cleaner; check for bent or backed-out pins
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5
Measure sensor resistance cold and again at operating temperature; compare both readings to the OEM resistance chart — an intermittent thermistor may read correctly when cold but drift when warm
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6
If harness and connectors appear sound, back-probe the circuit and log data over an extended drive cycle to capture the fault event; use a data logger if available
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7
Replace the sensor if resistance values are erratic or if the fault persists after harness repair
Related powertrain codes
- P0100 — Mass or Volume Air Flow A Circuit Malfunction
- P0101 — Mass or Volume Air Flow A Circuit Range/Performance Problem
- P0102 — Mass or Volume Air Flow A Circuit Low Input
- P0103 — Mass or Volume Air Flow A Circuit High Input
- P0104 — Mass or Volume Air Flow A Circuit Intermittent
- P0105 — Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction
Frequently asked questions
Why is P0184 harder to diagnose than P0180?
P0184 is an intermittent fault, meaning the circuit is not continuously broken — it only misbehaves under specific conditions such as vibration, heat, or moisture. The PCM may self-clear the symptom between tests, so reproducing the fault requires careful live-data monitoring while manipulating the wiring harness or driving under the conditions that originally triggered it.
Can P0184 set without any noticeable drivability symptoms?
Yes. If the intermittent dropout is very brief, the PCM may substitute a default value for only a fraction of a second, which is not long enough to produce a perceptible misfire or stumble. The MIL will still illuminate if the fault meets the frequency threshold, even if the driver notices nothing unusual.
Does clearing the code fix P0184?
No. Clearing the code only removes the stored fault and turns off the MIL temporarily. The underlying intermittent fault remains and will trigger the code again once the PCM detects the same erratic signal behaviour. The root cause must be physically repaired.
Is P0184 related to P0180?
Both codes relate to fuel temperature sensor A, but P0180 indicates a persistent out-of-range or missing signal while P0184 specifically flags intermittent signal dropout or implausible rapid changes. They can occur together on the same circuit, and resolving the intermittent fault (P0184) often resolves both codes simultaneously.
Disabling P0184 in software
RaceTune can permanently disable P0184 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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