P0452

CIRCUIT DESCRIPTION
The control module 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 control module supplies a 5-volt reference and ground to the sensor. The FTP sensor signal voltage increases as the fuel tank pressure decreases. In other words a negative EVAP system pressure or a vacuum will result in a high FTP voltage. The FTP sensor signal voltage decreases as the fuel tank pressure increases. In other words a positive EVAP system pressure will result in a low FTP voltage. When the FTP sensor signal goes below a predetermined value, DTC P0452 will set.

CONDITIONS FOR RUNNING THE DTC
The ignition is ON.

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

ACTION TAKEN WHEN THE DTC SETS
^ The control module will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
^ The control module will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module will turn OFF the MIL during the third consecutive trip in which the diagnostic ran and passed.
^ The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

TEST DESCRIPTION

Steps 1-4:

Steps 5-13:

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