GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Express (CNG) 🢒 DTC 🢒 DTC P1432

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 below 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 less than 0.45 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.

  1. This step determines if the condition is present.

    2.

  2. This step determines if the signal circuit of the FTP sensor is the cause of the condition.

    3.

  3. This step determines if the 5-volt reference circuit is the cause of the condition.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Alternative Fuels (Engine Controls)

2

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the Fuel Tank Pressure (FTP) data parameter with a scan tool.

Does the scan tool display the FTP sensor voltage less than the specified value?

0.45 V

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame and/or the Failure records data for this DTC.
  2. Turn the ignition OFF for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure records data.

Does the DTC fail this ignition cycle?

--

Go to Step 4

Go to Intermittent Conditions

4

  1. Remove the fuel tank cover. Refer to Fuel Tank Cover Replacement .
  2. Disconnect the harness connector of the FTP sensor.
  3. Measure the voltage from the 5-volt reference circuit of the FTP sensor with a DMM.

Is the voltage more than the specified value?

4.8 V

Go to Step 5

Go to Step 7

5

  1. Connect a 3-amp fused jumper wire between the signal circuit of the FTP sensor and the 5-volt reference circuit of the FTP sensor.
  2. Observe the FTP sensor data parameter with a scan tool.

Does the scan tool display the FTP sensor voltage more than the specified value?

4.7 V

Go to Step 8

Go to Step 6

6

Test for a short to ground or open on the signal circuit of the FTP sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

7

Test for an open or a short to ground on the 5 Volt reference circuit of the FTP sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8

Inspect for proper terminal contact at the harness connector of the FTP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

9

Inspect for proper terminal contact at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems in the G/H Van Service Manual.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

10

Replace the fuel tank pressure sensor. Refer to Fuel Tank Pressure Sensor Replacement .

Is the replacement complete?

--

Go to Step 12

--

11

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls in the G/H Van Service Manual.

Did you complete the replacement?

--

Go to Step 12

--

12
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30  seconds.
  3. Turn ON the ignition, with the engine OFF.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

--

Go to Step 2

Go to Step 13

13

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK