P0453

Circuit Description
The powertrain control module (PCM) monitors the fuel tank pressure sensor signal in order 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 volt reference and a ground to the sensor. The sensor returns a signal voltage between 0.1 and 4.9 volts. If the PCM detects a fuel tank pressure sensor signal that is excessively high, DTC P0453 is set.

Conditions for Running the DTC
The ignition is on.

Conditions for Setting the DTC
^ The fuel tank pressure sensor signal is greater than 4.9 volts.
^ This condition is present for 5 seconds.

Action Taken When the DTC Sets
^ The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has run and failed.
^ The PCM stores the conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC
^ The PCM turns the MIL Off during the third consecutive trip in which the diagnostic has run and passed.
^ The history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC may be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids
Inspect for the following conditions:
^ A faulty connection at the PCM or the fuel tank pressure sensor. Inspect the harness connectors for backed out terminals, improper mating broken locks, improperly formed or damaged terminals, and faulty 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 a scan tool while moving the connectors and wiring related to the sensor. A change in the display indicates the location of the malfunction.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
15. 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.