P0450
DTC P0450 or P0451
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0450
- Fuel Tank Pressure (FTP) Sensor Circuit
DTC P0451
- Fuel Tank Pressure (FTP) Sensor Performance
Typical Scan Tool Data
Circuit/System Description
The control module monitors the fuel tank pressure (FTP) sensor signal in order to detect vacuum decay and excess vacuum during the evaporative emission (EVAP) diagnostic test. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. This DTC sets if the engine control module (ECM) detects one of the following conditions:
* The FTP sensor signal voltage is not within a calibrated range on a cold start-up.
* The FTP sensor signal oscillates greater than a calibrated amount when vehicle speed is less than 30 km/h (50 mph).
The following table illustrates the relationship between FTP sensor signal voltage and the EVAP system pressure/vacuum.
Conditions for Running the DTC
P0450
* Before the ECM can report DTC P0450 failed, DTCs P2227, P2228, and P2229 must run and pass.
* DTC P0100, P0101, P0102, P0103, P0449, P0452, P0453, P0498, P0499, or P0700 is not set.
* The engine is operating.
* The ambient air temperature is greater than -8°C (+18°F).
* The vehicle speed is less than 30 km/h (19 mph).
* The ECM has commanded the EVAP canister vent solenoid valve closed.
* DTC P0450 runs continuously once the above conditions are met for approximately 27 seconds.
P0451
* Before the ECM can report DTC P0451 failed, DTCs P0450, P2227, P2228, and P2229 must run and pass.
* DTC P0100, P0101, P0102, P0103, P0449, P0452, P0453, P0461, P0462, P0463, P0498, P0499, P0501, P0502, or P215B is not set.
* The engine is operating.
* The engine has cycled ON and OFF greater than 6 to 16 times dependent on coolant temperature.
* DTC P0461, P0462, or P0463 is not set.
* The ambient air temperature is between 3-36°C (37-97°F).
* The vehicle speed is between 10-76 km/h (6-47 mph) for greater than 29 seconds.
* The BARO is greater than 68 kPa.
* The fuel level is between 8-62 percent.
* The ECM has commanded the EVAP canister purge solenoid OFF.
* The ECM has commanded the EVAP canister vent valve open.
* DTC P0451 runs continuously once the above conditions are met for greater than 2 seconds.
* DTC P0451 runs continuously once the above conditions are met for greater than 300 seconds if a refueling event has been detected, or a fuel level sensor DTC is set.
Conditions for Setting the DTC
P0450
The ECM detects that the FTP sensor signal oscillates greater than 6.09 mm/Hg (3.26 in. H2O) for 1 second.
P0451
* The ECM detects that the FTP is less than -26.2 mm/Hg (-14.1 in. H2O) or greater than 10.6 mm/Hg (5.7 in. H2O) for 11 seconds.
OR
* The ECM detects a change in the zero point of FTP sensor signal greater than +/-5.10 mm/Hg (+/-2.73 in. H2O) from the zero point at start up for 8 seconds.
Action Taken When the DTC Sets
* DTC P0450 is Type B DTC.
* DTC P0451 is Type B DTC.
Conditions for Clearing the MIL/DTC
* DTC P0450 is Type B DTC.
* DTC P0451 is Type B DTC.
Diagnostic Aids
* A blocked or clogged EVAP canister vent may set these DTCs.
* A large leak in the EVAP system could cause these DTCs to set.
Reference Information
Schematic Reference
Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Evaporative Emission Control System Description (Evaporative Emission Control System Description)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
* J 41413-SPT High Intensity White Light
* J 41413-VLV EVAP Port Vent Fitting Tool
* J 41413-200 Evaporative Emissions System Tester (EEST)
* J 41413-300 EVAP Cap and Plug Kit
* CH-48096 EVAP Service Port Access Tool
* GE-41415-50 Fuel Tank Cap Adapter
Circuit/System Testing
1. Ignition OFF, open the hood to disable the Auto-Stop function.
2. Ignition ON, verify the scan tool hood position parameter displays Open.
• If the hood position does not display Open, refer to DTC P254F (P254F).
3. Remove the fuel fill cap. Connect the GE-41415-50 to the fuel tank filler neck. Connect the J 41413-200 to the GE-41415-50 .
4. Seal the system using the Purge Seal function with a scan tool.
5. Pressurize the EVAP system with nitrogen to 5 inches H2O. Compare the Fuel Tank Pressure Sensor parameter to the J 41413-200 pressure/vacuum gage. The FTP sensor should be within 1 inch H2O of the pressure/vacuum gage.
• If the FTP is not within 1 inch H2O of the pressure/vacuum gage, replace the FTP sensor.
6. Command the vent solenoid valve OPEN with a scan tool.
• If the FTP sensor parameter is not 0 inch H2O, replace the FTP sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Fuel Tank Pressure Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming