Fuel Temperature Sensor 1 Circuit High
The fuel temperature sensor is reporting a voltage that is too high.
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What it means (plain English)
The fuel temperature sensor measures how hot the fuel is. If it sends a signal over 4.5 volts, the engine control module thinks there's something wrong because temperatures that high don’t make sense for fuel.
What the computer is actually seeing
The engine control module (ECM) sees a voltage reading from the fuel temperature sensor that exceeds the expected range, typically above 4.5 volts.
What a healthy reading looks like
Fuel temperature sensor output should be between 0.5 volts (around -40°C/-40°F) and 4.5 volts (around 150°C/302°F). Normal operation around 1.5 to 2.5 volts (20°C to 80°C).
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check the wiring and connectors for the fuel temperature sensor for damage or corrosion. Repair as needed.
- 2Using a multimeter, measure the voltage at the fuel temperature sensor. It should be between 0.5 and 4.5 volts. If it’s over 4.5 volts, continue to the next step.
- 3Disconnect the fuel temperature sensor and check the wiring harness for a short circuit to power (check for 12V+). If found, repair the wiring, then recheck the sensor readings.
- 4If the wiring is okay, replace the fuel temperature sensor, then clear the code and monitor for any return.
Common causes
- Faulty fuel temperature sensor
- Wiring issues (short to voltage)
- Bad ECM
- Incorrect fuel type used
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally safe to drive, but monitor engine performance as fuel temperature can impact combustion.
Will this code come back?
If the root cause isn't fixed, yes, it will likely return.
Why does this code pair with SPN 3230?
SPN 3230 is related to the same sensor circuit and may indicate a sensor fault or communication issue.
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