P0183

DTC P0183

Circuit Description

The fuel tank temperature (FTT) sensor is a variable resistor that measures the temperature of the fuel in the CNG fuel tank. The PCM supplies 5 volts to the FTT signal circuit. This DTC sets when the FTT signal voltage is above the normal operating range of the sensor.

Conditions for Running the DTC

- The ignition is ON.
- The intake air temperature is more than -35°C (-31°F).

Conditions for Setting the DTC

- The fuel tank temperature sensor voltage is more than 4.95 volt.
- The condition exists for more than 5 seconds.

Action Taken When the DTC Sets

- The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

Conditions for Clearing the DTC

- A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
- A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Use a scan tool in order to clear the DTC.

Diagnostic Aids

- Use the Temperature vs Resistance table in order to test the FTT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in a driveability condition. If the engine has sat overnight, the FTT sensor and the intake air temperature values should display within a few degrees. If the temperatures are not within 3°C (5°F), refer to Fuel Temperature Sensor Output Voltage Versus Temperature Resistance.
- For an intermittent condition, refer to Intermittent Conditions.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

4. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
8. This step tests the signal circuit of the FTT sensor for a short to another 5-volt reference circuit.