Faulty fuel temperature sensor or sensor circuit wiring (open, short, or high resistance); Restricted fuel return line or faulty fuel pressure regulator causing fuel to heat in the rail; Low fuel level combined with high ambient heat and prolonged idling, allowing fuel to absorb engine bay heat; Malfunctioning in-tank fuel pump or transfer pump that fails to circulate fuel and dissipate heat; Engine coolant temperature sensor bias or thermostat stuck closed, raising overall underhood temperatures; Aftermarket fuel system modifications or incorrect fuel blend that raises vapor pressure and temperature; Corroded or damaged connector pins at the fuel temperature sensor or powertrain control module

DTC codes / P01xx · Fuel and air metering / P0168

P0168Fuel Temperature Too High

Q: What does code P0168 mean?

Fuel Temperature Too High. P0168 means the engine control module has determined that the fuel temperature is higher than the expected range for current operating conditions. The computer compares the fuel temperature sensor signal against a modeled threshold and sets this code when the reading exceeds that limit for a calibrated time.

P0168 means the engine control module has determined that the fuel temperature is higher than the expected range for current operating conditions. The computer compares the fuel temperature sensor signal against a modeled threshold and sets this code when the reading exceeds that limit for a calibrated time.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Reduced engine power or limp mode in some vehicles when fuel temperature exceeds a safety limit
Hard starting or rough running after a hot soak, especially on engines with returnless fuel systems
Fuel odor or visible fuel seepage around the tank or lines in severe cases
Intermittent stalling or hesitation when fuel temperature spikes during low-fuel, high-load driving

Common causes, most likely first

Faulty fuel temperature sensor or sensor circuit wiring (open, short, or high resistance)
Restricted fuel return line or faulty fuel pressure regulator causing fuel to heat in the rail
Low fuel level combined with high ambient heat and prolonged idling, allowing fuel to absorb engine bay heat
Malfunctioning in-tank fuel pump or transfer pump that fails to circulate fuel and dissipate heat
Engine coolant temperature sensor bias or thermostat stuck closed, raising overall underhood temperatures
Aftermarket fuel system modifications or incorrect fuel blend that raises vapor pressure and temperature
Corroded or damaged connector pins at the fuel temperature sensor or powertrain control module

How to diagnose and fix it

Scan all modules and record freeze-frame data for P0168 to see fuel temperature, coolant temperature, and fuel level at the time of fault
Inspect the fuel temperature sensor connector and wiring for corrosion, chafing, or loose pins, and compare sensor resistance to the manufacturer's temperature chart
Verify fuel level and advise the customer to keep the tank above one quarter full during hot weather as a diagnostic step
Check fuel system pressure and return flow where applicable, looking for a restricted return line or failed pressure regulator
Test the in-tank fuel pump operation and confirm proper fuel transfer and circulation on split-tank or returnless systems
Compare fuel temperature sensor reading to a known-good value or infrared thermometer at the fuel rail after a cold soak
Replace the fuel temperature sensor or repair the circuit only after confirming the signal is skewed, then clear codes and verify the repair with a road test

Fuel temperature codes that mislead

A P0168 is frequently set by a fuel level that is too low for the ambient heat, so checking the fuel gauge and freeze-frame fuel level before replacing any part saves unnecessary sensor swaps.
On returnless fuel systems, the fuel temperature sensor often shares a circuit with the fuel level sender, so a faulty sender or chafed harness can bias the temperature reading without any sensor fault.
Technicians sometimes replace the fuel temperature sensor only to find the real cause is a stuck-closed thermostat raising underhood temperatures, so always cross-check coolant temperature behavior.
This code can be set by a fuel blend with high vapor pressure in hot climates, and it may clear on its own after refueling with a lower-volatility fuel, which is not a parts failure.
A restricted fuel filter or pinched return line can raise fuel temperature enough to set P0168 without any driveability complaint, so pressure and flow testing belongs in the diagnostic sequence.

Can I keep driving with P0168?

You can usually drive with P0168 if the engine runs normally, but avoid prolonged idling, heavy loads, and running with a low fuel tank until the cause is found. If the engine enters limp mode or you smell fuel, stop driving and have it inspected promptly.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.