P0453
CIRCUIT DESCRIPTIONThe 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.
^ Use a scan tool in order to clear the MIL and the DTC.
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 and Poor Connections in Diagrams.
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 - Computers and Control Systems. Standard Model (Non-Alternative Fuels)
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 above shows how the values compare:
TEST DESCRIPTION
Steps 1-8:
Steps 9-16:
The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the 5-volt reference circuit is shorted to a voltage.
3. This step determines if a fault is present.
4. 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.
5. This step tests whether the signal circuit is shorted to a voltage.
6. This step tests whether a ground circuit is available at the fuel tank pressure sensor connector.
8. This step tests the ground circuit for an open.