Powertrain Controls Diagnosis (BI-Fuel)

DTC P1433

Circuit Description

The fuel tank pressure (FTP) sensor is a pressure transducer. The powertrain control module (PCM) supplies about 5 volts on the FTP sensor reference voltage circuit. The PCM also supplies a signal 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 PCM 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 greater than the normal operating range of the sensor.

Conditions for Running the DTC

- DTCs P0182, P0183 are not set.
- The fuel tank temperature (FTT) is less than 65°C (149°F).

Conditions for Setting the DTC

- The FTP signal voltage is more than 4.75 volts.
- The condition exists for at least 1 second.

Action Taken When the DTC Sets

- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the 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

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 an open sensor ground circuit condition is present. The FTP and FTT share a sensor ground. An open circuit between the splice and the ground terminal will cause both signal circuits to indicate high voltage.
5. This step determines if an open or shorted signal circuit is the cause of the condition.
6. This step determines if a shorted 5-volt reference circuit is the cause of the condition.
7. This step determines if an open sensor ground circuit between the harness connector of the FTP sensor and the splice is the cause of the condition.