P0168

DTC P0168

CIRCUIT DESCRIPTION
The fuel temperature sensor is a thermistor type sensor. The engine control module (ECM) supplies 5 volts and a ground circuit to the sensor. When the ECM detects a fuel temperature sensor above a pre-determined value, a type C code, no malfunction indicator lamp (MIL) sets. A fuel cooler located in front of the fuel tank is used to help keep the fuel temperature at an acceptable limit.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0168 Engine Fuel Over-Temperature

CONDITIONS FOR RUNNING THE DTC
- The ignition is ON.
- DTC P0168 runs continuously within the enabling conditions.

CONDITIONS FOR SETTING THE DTC
The fuel temperature sensor is above 122°C (252°F) for more than 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
- The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE DTC
- A current DTC Last Test Failed clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Clear the DTC with a scan tool.

TEST DESCRIPTION

Steps 1-10:

Steps 11-12:

The numbers below refer to the step numbers on the diagnostic table.
2. This step inspects for a condition in the fuel cooler that could cause the fuel temperature sensor to increase above the pre-determined specification due to a lack of cooler efficiency.
5. This step tests for a voltage above or below the 5 volts supplied by the ECM.