P0450 (W/O ORVR)

CIRCUIT DESCRIPTION
The DTC P0450 Fuel Tank Pressure (FTP) Sensor Circuit diagnostic monitors the fuel tank pressure sensor voltage. The fuel tank pressure sensor responds to changes in the fuel tank pressure or vacuum. The fuel tank pressure sensor signal voltage to the Powertrain Control Module (PCM) varies from more than 4 volts with pressure in the fuel tank, to a minimum of 0.6 volts with a high vacuum condition in the fuel tank.

CONDITIONS FOR RUNNING THE DTC
^ The Barometric Pressure (BARO) is more than 75 kPa.
^ The intake air temperature is -8 to +40°C (18-104°F).
^ The engine coolant temperature is -8 to +110°C (18-230°F).
^ The engine is running.

CONDITIONS FOR SETTING THE DTC
The FTP sensor voltage is less than 0.5 volts for a specified time.

OR

The FTP sensor voltage is more than 4.5 volts for a specified time.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) after 2 consecutive ignition cycles in which the diagnostic runs with the fault active.
^ The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The MIL turns off after 3 consecutively passing trips without a fault present.
^ A history DTC clears after 40 consecutive warm-up cycles without a fault.
^ Perform the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS
Check for any of the following conditions:
^ A plugged sensor air vent hole. Inspect the sensor and clean if necessary.
^ If multiple DTCs are set, it may be possible to have an open or a shorted reference voltage circuit or an open ground circuit.

If a DTC P0450 is intermittent, driving the vehicle under the conditions outlined in the Inspection/Maintenance (I/M) section can verify whether the fault is present. Refer to Inspection/Maintenance (I/M) Evaporative Emission (EVAP) System Set Procedure. I/M Evaporative Emission (EVAP) System Set Procedure

An intermittent malfunction may be caused by a fault in the fuel tank pressure sensor circuit. Inspect the wiring harness and components for an intermittent condition. Refer to Intermittent Conditions. Intermittent Conditions

If the DTC P0450 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

TEST DESCRIPTION

Steps 1-10:

Steps 11-19:

The numbers below refer to the step numbers in the diagnostic table.
1. The Diagnostic System Check-Computers and Control Systems prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. Determine if a fault is present. Review the Freeze Frame data to determine the conditions when the DTC set. Always record this information.
9. This step verifies that the fuel tank pressure sensor accurately reacts to EVAP system pressure changes. This also checks the sensor signal input circuit.
11. This step checks the operation of the fuel tank pressure (FTP) control valve.