P0452

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Fuel Tank Pressure Sensor responds to changes in the fuel tank pressure or vacuum. This information is used in order to detect vacuum decay or an excessive vacuum during the EVAP diagnostic routing. The fuel tank pressure sensor signal voltage to the VCM varies from a minimum of about 0.1 volts with pressure in the fuel tank to above 4.0 volts with a high vacuum in the fuel tank.

The Fuel Tank Pressure sensor display on the scan tool has an auto zero feature which occurs at each ignition cycle and is corrected according to the barometric pressure. Because of this, the Fuel Tank Pressure sensor display may not accurately reflect the actual output of the sensor or the conditions within the fuel tank.

The Fuel Tank Pressure Sensor diagnosis table is intended to isolate and diagnose the electrical problems with the sensor wiring or the sensor.

CONDITIONS FOR SETTING THE DTC

The Fuel Tank Pressure Sensor voltage is less than 0.1 volt for more than 5 seconds.

ACTION TAKEN WHEN THE DTC SETS

The VCM turns ON the MIL after 2 consecutive driving cycles with the fault active.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The VCM turns the MIL OFF after 3 consecutive drive trips when the test has Run and Passed and not Failed.

^ A history DTC will clear it no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle).

^ Use the scan tool Clear Information function.

^ Disconnect the VCM battery feed for 30 seconds.

DIAGNOSTIC AIDS

1. Inspect the Control Module harness connectors for the following conditions:

^ Improper mating

^ Broken locks

^ Improperly formed

^ Damaged terminals

2. Inspect the wiring harness for damage. If the harness appears to be OK observe the Fuel Tank Pressure sensor display on the scan tool while moving the connectors and the wiring harnesses related to the sensor. A change in the display will indicate the location of the fault. Refer to Wiring Repairs in Electrical Diagnosis if a fault in the wiring is found.

TEST DESCRIPTION

The number(s) below refer to the step number(s) on the diagnostic table.

5. A normal Fuel Tank Pressure Sensor signal voltage without any pressure or vacuum in the fuel system should be between 1.30 volts and 2.0 volts. If the voltage is out of this range a skewed (out of range) sensor or damaged wiring could be at fault.