P0452

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) monitors the Fuel Tank Pressure (FTP) sensor signal in order to detect vacuum decay and excess vacuum during the enhanced Evaporative Emission (EVAP) diagnostic. The PCM supplies a 5-volt reference and ground to the sensor. The FTP sensor signal voltage increases as the fuel tank pressure decreases (negative pressure or vacuum, high voltage). The FTP sensor signal voltage decreases as the fuel tank pressure increases (positive pressure, low voltage). This DTC sets when the FTP sensor signal goes below a predetermined value.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
^ The fuel tank pressure sensor voltage is less than 0.1 volts.
^ All conditions present for greater than 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ First failure:
- The MIL is not turned ON.
- A DTC is stored in memory under Failed Last Test.
- The Failure Records are stored.
^ Second consecutive drive cycle with a failure:
- The MIL is turned ON.
- A DTC is stored in memory under history.
- The Freeze Frame data is stored.
- The Failure Records are stored.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after the third consecutive trip the diagnostic has run and passed.
^ The history DTC will clear if the fault conditions have not been detected for 40 warm-up cycles.
^ A scan tool can be used to clear DTC information.

TEST DESCRIPTION

Steps 1-4:

Steps 5-13:

The number below refers to the step number on the diagnostic table.
5. Tests for the proper operation of the circuit in the high voltage range.