Advanced Diagnostics

Advanced Diagnostics

DTC P0181: Fuel Temperature Sensor Circuit Range/Performance Problem






General Description
The powertrain control module (PCM) measures the fuel temperature immediately before the injection of the CNG and corrects the air density of the CNG.
When the engine stops and enough time has passed, each part of the vehicle becomes the same temperature as the ambient air.
At step 1, the two coolant temperature sensors are compared to judge if the intake temperature sensor reading is normal. When the intake temperature sensor is judged as normal, the intake temperature sensor and CNG fuel temperature sensor are compared at step 2, and if an improper temperature is detected, a CNG fuel temperature sensor problem is detected and a DTC is stored.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
When the temperature difference between the fuel temperature sensor and IAT is 45 °F (25 °C) or more.

Driving Pattern

1. Turn the ignition off, and wait at least 6 hours.
2. Start the engine, and let it idle for at least 10 seconds.

Diagnosis Details

Conditions for illuminating the MIL
When a malfunction is detected during the first drive cycle, a Temporary DTC is stored in the PCM memory. If the malfunction recurs during the next (second) drive cycle, the MIL comes on and the DTC and the freeze frame data are stored.

Conditions for clearing the MIL
The MIL will be cleared if the malfunction does not recur during three consecutive trips in which the diagnostic runs.
The MIL, the DTC, the Temporary DTC, and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.