P0453
DTC P0453CIRCUIT DESCRIPTION
The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage increases above a calibrated value, this DTC sets.
The table illustrates the relationship between FTP sensor signal voltage and the EVAP system pressure/vacuum.
CONDITIONS FOR RUNNING THE DTC
The engine is running.
CONDITIONS FOR SETTING THE DTC
- The FTP sensor voltage is more than 4.9 volts.
- All conditions are present for more than 25 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 DTC
- 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 non-emission related diagnostic.
- Clear the DTC with a scan tool.
DIAGNOSTIC AIDS
- If DTC P0105 is also set, a short to voltage on the 5-volt reference circuit may exist.
- The A/C pressure sensor, the FTP sensor and the throttle position (TP) sensor are all tied to the same 5-volt reference source.
- To locate an intermittent problem, use the scan tool to monitor FTP sensor voltage with the ignition ON, the engine OFF. Wiggling wires while watching for a change in FTP sensor voltage may locate the area where an open or a short to voltage in the wiring could lie.
- The signal voltage with the fuel cap OFF should read between 2.35-2.85 volts, which represents atmospheric pressure or 0 inches of vacuum.
- Inaccurate readings will occur if resistance measurements are taken on a FTP sensor. The FTP sensor contains an internal amplifier circuit that requires applied voltage to function properly.
TEST
