Fuel Temperature Sensor 1 - Voltage Below Normal
This code indicates that the fuel temperature sensor is reporting a voltage that is lower than expected.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The fuel temperature sensor measures how hot the fuel is. If it's reading lower than it should, the computer might think the fuel is colder than it is, which can affect fuel injection timing.
What the computer is actually seeing
The ECU expects the fuel temperature to be between 0-180°F (approximately -18 to 82°C). If the voltage signal from the fuel temperature sensor is below 0.5V, it triggers this code.
What a healthy reading looks like
Expected voltage range should be between 0.5V (below normal) to 4.5V (normal operation).
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.
- 11. Check the vehicle's fuel level and quality to rule out fuel issues. Confirm that you have enough fuel and it meets specifications.
- 22. Inspect the wiring and connector for the fuel temperature sensor. Look for broken wires, corrosion, or loose connections. Repair as needed.
- 33. Measure the voltage at the fuel temperature sensor connector with the key in the ON position (engine OFF). You should see a voltage between 0.5V and 4.5V. If it's below 0.5V, the sensor may be faulty.
- 44. If the voltage is okay, check the sensor itself by removing it and placing it in hot water to see if the voltage increases proportionally to temperature. Should match expected values.
- 55. If the sensor fails the test, replace it and clear the codes. If the voltage readings are intermittently low, suspect wiring issues.
Common causes
- Damaged or corroded wiring to the fuel temperature sensor
- Faulty fuel temperature sensor
- Poor connection at the sensor or ECM
- Low fuel temperature due to extreme weather conditions
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but monitor performance as it can affect fuel economy and emissions.
Will this code come back after clearing?
If the underlying issue isn't resolved, the code will likely return.
Why does this code sometimes pair with SPN 0696?
SPN 0696 is related to the same fuel temperature sensor but indicates a high voltage, showing the sensor may be faulty.
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