P0168 code meaning
Fuel Temperature Too High
Powertrain system Generic code P01xx codes Check engine light
What P0168 means
P0168 is not a sensor fault but an operating condition, almost only on diesels: the fuel temperature sensor reports fuel hotter than a protective limit. The fuel heats up through the return flow from the high-pressure pump and injectors, especially with little fuel in the tank, at idle after full load, in hot weather or with a failed fuel cooler; one manufacturer patent names about 80 °C as the upper limit to protect seals, against a normal range of roughly 5–60 °C. On Saab's Bosch EDC16 diesels the code means an engine protection function is active and injection quantity is reduced. No manufacturer threshold was found, and GM's and Ford's diesel summaries do not use P0168. Whether the warning light comes on depends on the manufacturer.
P0168 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor1 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0168
- Loss of power, limp mode (reduced injection quantity)
- Warning light depending on manufacturer
- Occurs in heat, at full load, with little fuel in the tank
Common causes of P0168
- Most likelyFuel cooler (air or water cooler in the return) dirty or faulty, coolant circuit disturbed
- PossibleVery little fuel in the tank at high load or heat
- PossibleExcessive return flow from worn high-pressure pump or injectors, or faulty overflow valve
- PossibleFuel temperature sensor drifting and reading too high
- Less likelyEngine overheating or overload (trailer, gradient)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel temperature sensor aFuel coolerFuel return line
What each part of P0168 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| 68 | The exact fault in that area. |
What to do next
- Note P0168 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0168
What does P0168 mean?
P0168 means "Fuel Temperature Too High". P0168 is not a sensor fault but an operating condition, almost only on diesels: the fuel temperature sensor reports fuel hotter than a protective limit. It is a generic code, so it means the same on every make.
Is it safe to drive with P0168?
Drive gently and only to a workshop. With P0168 the car can go into limp mode (reduced power) to protect itself.
Will P0168 fail an emissions test?
P0168 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P0168 to fix?
Difficulty: medium. A typical repair takes 1 to 3 hours of work. This is a job for a workshop.
Will P0168 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.