P1432

DTC P1432

CIRCUIT DESCRIPTION
The compressed natural gas (CNG) fuel tank pressure (FTP) sensor is a pressure transducer. The fuel injector control module (FICM) supplies about 5 volts on the FTP sensor reference voltage circuit. The FICM also supplies a signal circuit and a low reference 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 FICM communicates the FTP data to the powertrain control module (PCM) by a pulse width modulated (PWM) circuit. The PCM uses the FTP sensor and the fuel tank temperature (FTT) sensor in order to determine 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.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P1432 Fuel Pressure Sensor Circuit Low Voltage

CONDITIONS FOR RUNNING THE DTC
- The ignition voltage is between 6-18 volts.
- The engine is cranking or running.

CONDITIONS FOR SETTING THE DTC
- DTC P1207 is not set.
- The FTP signal voltage is less than 0.1 volts.
- The condition exists for at least 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module switches over to gasoline fuel operation.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- 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 emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

Step 1 - Step 11:

Step 12 - Step 13:

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.