P0452

Diagnostic Chart:

Schematic:

The Evaporative Emission (EVAP) system is used to store fuel vapors as to reduce the amount of unburned fuel from escaping into the atmosphere. The function of the fuel tank pressure sensor is solely for EVAP leak diagnostics. The fuel tank pressure sensor is a transducer that varies resistance according to changes in fuel tank pressure. The PCM measures the signal voltage from the fuel tank pressure sensor, which is a reduced value of the PCM 5 volt reference. The signal voltage will read high when the pressure in the fuel tank is low (vacuum) and will decrease as the pressure in the tank increases. DTC P0452 sets when the signal voltage at the PCM is below the calibrated voltage value.

DTC PARAMETERS
DTC P0452 will set if fuel tank pressure sensor voltage is less than 0.1 volts when:
^ Condition exists for longer than 0.3 seconds
^ Ignition is On

DTC P0452 diagnostic runs continuously with ignition On.

DTC P0452 is a type A DTC.

DIAGNOSTIC AIDS

IMPORTANT: If DTC P1635 is also set, diagnose that DTC first.

To locate an intermittent problem, use Scan tool to monitor FUEL TANK PRESS. SENSOR voltage with ignition On, engine Off. Wiggling wires while watching for a change in FUEL TANK PRESS. SENSOR voltage may locate the area where an open or short to ground in the wiring could lie.

The signal voltage with the fuel cap Off should read 1.3-1.7 volts, which represents atmospheric pressure (101 kPa or 14.7 psi).

IMPORTANT: Inaccurate readings will occur if resistance measurements are taken on a fuel tank pressure sensor. The fuel tank pressure sensor contains an internal amplifier circuit that requires applied voltage to function properly.