Fuel Temperature Sensor A Circuit High Input
The fuel temperature sensor is reporting a voltage that's too high, like a thermometer reading impossibly hot. The engine computer thinks the fuel is much hotter than it actually is.
The ECU monitors the fuel temperature sensor's voltage output to adjust fuel injector timing and quantity. The sensor uses a thermistor that changes resistance based on fuel temperature, converting to a voltage signal. When voltage exceeds the maximum threshold, the ECU triggers P0184.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor Voltage | 0.5-4.5V (approximately -40°C to 125°C) | >4.8V or open circuit condition |
| Fuel Temperature Range | -40°C to 125°C | Reading above sensor maximum or sensor disconnected |
Code P0184 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0184 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.