P0452

DTC P0452

CIRCUIT DESCRIPTION
The evaporative emission (EVAP) system is used to store fuel vapors in order to reduce the amount of fuel vapors into the atmosphere. The fuel tank pressure (FTP) sensor is only used for EVAP system diagnostics. The FTP sensor is a transducer that varies resistance according to changes in the fuel tank pressure. The engine control module (ECM) monitors the FTP sensor signal in order to detect vacuum decay and excess vacuum during the EVAP system diagnostic test. The ECM supplies a 5 volt reference and a low reference circuit to the FTP sensor. If the ECM detects that the FTP sensor signal voltage is too low, this DTC sets.




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

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0452 Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage

CONDITIONS FOR RUNNING THE DTC
The ignition is ON, or the engine is running.
DTC P0452 runs continuously.

CONDITIONS FOR SETTING THE DTC
The FTP sensor voltage is less than 0.2 volt, for more than 1 second.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

Step 1:

Steps 2-4:

Steps 5-10:

Steps 11-12:

The number below refers to the step number on the diagnostic table.
4. This step tests for the proper operation of the circuit.