Powertrain Management (CNG)

DTC P1432

Circuit Description

The fuel tank pressure (FTP) sensor is a pressure transducer. The Alternative Fuels ECM supplies about 5 volts on the FTP sensor reference voltage circuit. The Alternative Fuels ECM also supplies a ground circuit to the FTP sensor. When fuel level/tank pressure is full the FTP signal voltage rises to 4.1 volts. As fuel level/tank pressure decreases to empty, the FTP signal voltage drops to around 0.5 volts. The Alternative Fuels ECM monitors the FTP signal circuit voltage and the Fuel Tank Temperature (FTT) sensor and determines the amount of fuel within the fuel tank.


This DTC sets when the FTP sensor signal voltage is below the normal operating range of the sensor.


Conditions for Running the DTC

The engine is operating on alternative fuel.


Conditions for Setting the DTC

The Alternative Fuels ECM monitors an FTP signal voltage of less than 0.5 volts for at least 1 second continuously.


Action Taken When the DTC Sets

* The Alternative Fuels ECM will NOT illuminate the MIL.
* The Alternative Fuels ECM will store this DTC as History during one drive trip in which the diagnostic runs and fails.
* The Alternative Fuels ECM will record operating conditions at the time the DTC sets. This information will be stored as Freeze Frame data.



Conditions for Clearing the DTC

* The Last Test Failed status will clear when the DTC runs and passes.
* The History status will clear after 40 consecutive WARM-UP cycles with NO failures of ANY DTC.
* All DTC Information can be cleared using a scan tool.



Test Description

The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the condition is present.
4. This step determines if the signal circuit of the FTP sensor is the cause of the condition.
5. This step determines if the 5-volt reference circuit is the cause of the condition.