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 5.0-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). 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 sensor voltage is less than 0.1 volts
^ All conditions present for greater than 5.0 seconds.

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

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM 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 numbers below refer to the step numbers on the diagnostic table.
2. If DTC P1639 sets, the 5-volt reference may be shorted to ground.
5. If the FTP sensor voltage is near 5 volts, the FTP sensor signal and 5-volt reference circuits are OK from the fuel tank harness connector to the PCM.