P0168 — Fuel Temperature Too High
What P0168 means
The engine control module uses the fuel temperature sensor to adjust fueling for changes in fuel density and vapor formation. P0168 sets when the reported temperature goes above the acceptable limit. The cause may be genuinely overheated fuel, or a faulty sensor or circuit giving a false reading.
Symptoms
- Check Engine light is on
- Worse fuel economy
- Rough or unstable idle
- Hesitation or loss of power
- Hard hot start or long cranking
Possible causes
- Faulty fuel temperature sensor (or fuel composition sensor on vehicles that use one)
- Open, shorted or corroded wiring and connectors in the sensor circuit
- Genuinely hot fuel from a restricted return line or poor heat dissipation
- Heat soak from nearby hot components such as the exhaust
- Control module software fault (uncommon)
- Failed control module (rare)
How to diagnose
- Read all codes and freeze-frame data and look for other fuel system codes
- Inspect the sensor, connector and harness for heat damage, chafing, moisture and corrosion
- On a cold engine, compare scan-tool fuel temperature with coolant temperature; they should be close
- Check sensor supply voltage, ground and reference signal at the connector with a multimeter
- Measure sensor resistance and compare it with the specification for your vehicle
- Check fuel pressure, return line flow and fuel filter condition
- Inspect heat shields and routing of fuel lines near hot parts
- If everything checks out, look for a software update before suspecting the module
Common fixes
- Replace the fuel temperature sensor
- Repair the wiring or connector and clean the terminals
- Clear a restricted return line or filter, or fix a faulty fuel cooler
- Restore missing heat shielding near fuel lines
- Update software or replace the control module if confirmed faulty
Questions and answers
What does P0168 mean?
The engine control module is seeing fuel temperature that is too high. It may be real overheating, or a bad sensor or wiring giving a false reading.
Can I drive with P0168?
Briefly, yes, but don't ignore it. If you notice misfires, hard starting or power loss, get it checked soon.
How can I tell a bad sensor from truly hot fuel?
On a cold engine, fuel temperature should be close to coolant temperature. If the sensor reads far higher, the sensor or its circuit is the likely culprit rather than the fuel.
This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.