GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Express 🢒 Engine 🢒 Engine Controls - 4.3L 🢒 DTC P0453

Circuit Description

The fuel tank pressure (FTP) sensor changes resistance based on the fuel tank pressure, or vacuum. A vacuum is considered negative pressure.

The powertrain control module (PCM) provides a 5-volt reference and a ground. The fuel tank pressure sensor signal varies between ground and 5 volts as the fuel tank pressure varies. The FTP sensor voltage increases as the fuel tank pressure decreases, such as negative pressure, or vacuum. The fuel tank pressure sensor voltage decreases, such as positive pressure, or low voltage, as the fuel tank pressure increases. The PCM uses the FTP sensor voltage for evaporative emission (EVAP) system leak detection. This diagnostic trouble code (DTC) sets when the FTP sensor signal goes above a predetermined value.

Conditions for Running the DTC

The ignition switch is in the RUN position.

Conditions for Setting the DTC
    • The fuel tank pressure sensor voltage is more than 4.90 volts.
    • All conditions are present for more than 5 seconds.

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.

Diagnostic Aids

Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.

The EVAP pressure sensor range is from +7.5 inch H2O of pressure to -17.5 inch H2O of pressure, or vacuum.

Inspect for poor connections at connector C152. This connector is located under the underhood electrical center. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

NOTE: An open ground circuit does not set DTC P0453. Still use the diagnostic if you were sent here from DTC P0446.

For an intermittent, refer to Symptoms - Engine Controls .

The vacuum and pressure in the EVAP system is measured in inches of water (H2O). Most gauges measure vacuum in inches of mercury (Hg) and pressure in pounds per square inch (psi). The following shows how the values compare:

in H2O

in Hg

psi

1in H2O

0.07 in Hg

0.0361 psi

5 in H2O

0.36 in Hg

0.180 psi

10 in H2O

0.73 in Hg

0.361 psi

15 in H2O

1.10 in Hg

0.541 psi

Test Description

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

  1. This step determines if the 5-volt reference circuit is shorted to a voltage.

  1. This step determines if a fault is present.

    2.

  2. Using the Freeze Frame/Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records data can help determine how many miles since the DTC set. The Fail Counter and the Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass or a fail. Operate the vehicle within the same Freeze Frame conditions, such as RPM, load, vehicle speed, temperature etc., that you observed. This will isolate when the DTC failed.

    3.

  3. This step tests whether the signal circuit is shorted to a voltage.

    4.

  4. This step tests whether a ground circuit is available at the fuel tank pressure sensor connector.

  5. This step tests the ground circuit for an open.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Are DTCs 1635 and 1639 also set?

--

Go to DTC P1635

Go to Step 3

3

Important: The ignition must be OFF for a minimum of 15 seconds when you are instructed to turn the ignition OFF. If the ignition switch is not in the OFF position for 15 seconds, misdiagnosis occurs. This information applies to every step that instructs you to turn OFF the ignition.

  1. Turn OFF the ignition for 15 seconds.
  2. Turn ON the ignition, with the engine OFF.
  3. Monitor the fuel tank pressure sensor voltage on the scan tool.

Is the fuel tank pressure sensor voltage above the specified value?

4.3 V

Go to Step 5

Go to Step 4

4

  1. Turn ON the ignition, with the engine OFF.
  2. Review the Freeze Frame/Failure Records data for this DTC and observe the parameters.
  3. Turn OFF the ignition for 15  seconds.
  4. Idle the engine.
  5. Operate the vehicle within the conditions required for this diagnostic to run, and as close to the conditions recorded in the Freeze Frame/Failure Records as possible. Special operating conditions that you need to meet before the PCM will run this diagnostic, where applicable, are listed in Conditions for Running the DTC.
  6. Select the Diagnostic Trouble Code (DTC) option, the Specific DTC option, then enter the DTC number using the scan tool.

Does the scan tool indicate that this diagnostic failed this ignition?

--

Go to Step 5

Diagnostic Aids

5

  1. Turn OFF the ignition for 15 seconds.
  2. Disconnect the fuel tank pressure sensor electrical connector at the fuel tank.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the fuel tank pressure sensor voltage display on the scan tool.

Is the fuel tank pressure sensor voltage below the specified value?

1 V

Go to Step 6

Go to Step 7

6

Probe the sensor ground circuit with the test lamp connected to B+. Refer to Probing Electrical Connectors in Wiring Systems.

Is the test lamp illuminated?

--

Go to Step 11

Go to Step 8

7

Measure the voltage from the fuel tank pressure sensor signal circuit at the harness connector to the battery ground using the DMM .

Is the voltage near the specified value?

0 V

Go to Step 14

Go to Step 9

8

  1. Disconnect the PCM connector C1 located on the same side as the manufacturers logo. Refer to Powertrain Control Module Replacement .
  2. Test for continuity of the fuel tank pressure sensor ground circuit between the PCM and the fuel tank pressure sensor electrical connector. Refer to Testing for Continuity in Wiring Systems.

Does the DMM display continuity within the specified range?

0-5 ohms

Go to Step 12

Go to Step 10

9

Repair the signal circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 15

--

10

Repair the open or high resistance in the ground circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 15

--

11
  1. Inspect for a poor ground connection at the fuel tank pressure sensor connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If you find a poor connection, repair the terminal as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 13

12
  1. Inspect for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If you find a poor connection, repair the terminal as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 14

13

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

Is the action complete?

--

Go to Step 15

--

14

Important: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement .

Is the action complete?

--

Go to Step 15

--

15
  1. Use a scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 16

Go to Step 2

16

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK