P0452

CIRCUIT DESCRIPTION
The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage goes below a calibrated value, this DTC sets.




The above table illustrates the relationship between the FTP sensor signal voltage and the EVAP system pressure/vacuum.

CONDITIONS FOR RUNNING THE DTC
The key is ON.

CONDITIONS FOR SETTING THE DTC
^ The FTP voltage is less than 0.1 volt.
^ All conditions present for greater than 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic tails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The malfunction indicator lamp (MIL) will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault.
^ A history DTC will clear after 40 consecutive warm-up cycles without a fault.
^ Use a scan tool in order to clear the DTCs.

TEST DESCRIPTION

DTC P0452 - Steps 1-4:

DTC P0452 - Steps 5-15:

The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies that the condition is present.
4. This step tests the 5-volt reference of the FTP sensor.
5. This step tests if another component is causing the 5-volt reference circuit condition. If the voltage increases when a component is disconnected, replace that component.
6. If the scan tool displays 5 volts, the FTP sensor signal circuit, the FTP sensor 5-volt reference circuit and the control module are OK.