P0452

Diagnostic Chart 1 Of 2:

Diagnostic Chart 2 Of 2:

Schematic:

CIRCUIT DESCRIPTION
The PCM monitors the fuel tank pressure sensor signal to detect vacuum decay and excess vacuum during the enhanced EVAP diagnostic. The fuel tank pressure sensor measures the difference between the air pressure (or vacuum) in the tank and the outside air pressure. The PCM applies a 5.0 volt reference and ground to the sensor. The sensor will return a signal voltage between 0.1-4.9 volts. If the PCM detects a fuel tank pressure sensor signal that is excessively low, DTC P0452 will set.

CONDITIONS FOR RUNNING THE DTC
The ignition is ON.

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

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test runs and fails.
^ The PCM stores conditions that were present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic runs and passes.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.

DIAGNOSTIC AIDS
Check for the following conditions:
^ Poor connection at the PCM or fuel tank pressure sensor
Inspect the harness connectors for backed out terminals, improper mating broken locks, improperly formed or damaged terminals, and poor terminal to wire connections
^ A damaged harness
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 connectors and wiring related to the sensor. A change in the display will indicate the location of the malfunction.

TEST DESCRIPTION
Number(s) below refer to the step number(s) on the Diagnostic Table.
12. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.