P0450

DTC P0450 Evaporative Emissions (EVAP) System Pressure Sensor Circuit (1 Of 2):

DTC P0450 Evaporative Emissions (EVAP) System Pressure Sensor Circuit (2 Of 2):

Evaporative Emissions (EVAP) System:

CIRCUIT DESCRIPTION

The fuel tank pressure sensor response to changes in fuel tank pressure or vacuum. The fuel tank pressure sensor signal voltage to the ECM varies from a minimum of about 0.2 volts with pressure in the fuel tank to above 4 volts with a high vacuum situation in the fuel tank (vent solenoid stuck closed).


CONDITIONS FOR SETTING THE DTC

Input range check:


- Voltage less than 0.5 volts.

- Voltage greater than 4.8 volts.

- condition present for 0.5 seconds.


ACTION TAKEN WHEN THE DTC SETS

- The Malfunction Indicator Lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the fault active.

- The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame buffer.


CONDITIONS FOR CLEARING THE MIL/DTC

- The MIL will turn "OFF" after three consecutive drive cycles without a fault present.

- A DTC will clear after 40 consecutive warm-up cycles without a fault.

- DTC(s) can be cleared by using a scan tool or by disconnecting the ECM battery feed.


DIAGNOSTIC AIDS


Check the following conditions:

- Poor connection at ECM. Inspect harness connectors for backed out terminal, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

- Damaged harness. Inspect the wiring harness for damage.

- Plugged sensor air vent hole. Inspect sensor and clean if necessary.

- If multiple DTC(s) are set it may be possible to have an open or shorted reference voltage circuit or an open ground circuit.

If 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 last set. This may assist in determining how often the DTC sets.

If any wiring repairs need to be made, Refer to Repair Procedures in Diagrams.


TEST DESCRIPTION

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

1. The Powertrain OBD System Check 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 Freeze Frame data to determine the condition of when the DTC set. Always record this information.

8. Verifies that the fuel tank pressure sensor accurately reacts to Evaporative Emissions (EVAP) system pressure changes. This also checks the sensor signal input circuit.

10. Checks the operation of the tank pressure control valve.