P0450
DTC P0450, P0452, or P0453
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 P0452
- Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage
DTC P0453
- Fuel Tank Pressure (FTP) Sensor Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The FTP sensor is used to detect any unexpected pressure in the EVAP system. The PCM supplies a 5-volt reference, an electrical ground, and a signal return circuit that has a 5-volt bias. The FTP sensor contains a silicon based chip that changes electrical resistance when pressure is applied. The sensor converts the positive or the negative pressure into an electrical signal and sends the signal to the PCM.
Conditions for Running the DTC
* The engine is running.
* The intake air temperature is between 4-35°C (40-95°F).
* The DTC P0450, P0452 and P0453 run once per ignition cycle when the above conditions are met.
Conditions for Setting the DTC
P0450
* The FTP sensor signal indicates a pressure less than -30 mm Hg (-16.32 in H2O) for 7 seconds.
OR
* The FTP sensor signal indicates a pressure greater than 15 mm Hg (8 in H2O) for 7 seconds.
P0452
The FTP sensor signal indicates a pressure less than -30 mm Hg (-16.32 in H2O) for 7 seconds.
P0453
The FTP sensor signal indicates a pressure greater than 15 mm Hg (8 in H2O) for 7 seconds.
Action Taken When the DTC Sets
DTC P0450, P0452, and P453 are Type A DTCs.
Conditions for Clearing the DTC
DTC P0450, P0452, and P453 are Type A DTCs.
Diagnostic Aids
* If a shared 5-volt reference circuit is shorted to ground the engine will not start and the PCM will not communicate with the scan tool.
* The EVAP system diagnostic can be monitored on the scan tool under the I/M System Information selection. When the EVAP test displays a YES status, indicating that the system diagnostic is completed, check for DTC P0450, P0452, or P0453 in the Last Test Failed screen of the scan tool. If there is no FTP sensor DTC displayed the EVAP system diagnostic has run and passed, indicating that no malfunction was present this time. DTCs MUST be cleared in order to view the Current Status of the system diagnostics being performed. Do not forget that the I/M System Information tests only indicate that the test has run, not if the test passed or failed. The Last Test Failed screen must be checked for related DTCs in order to determine the outcome of the diagnostic test involved.
Reference Information
Schematic Reference
Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
* Powertrain Control Module Connector End Views (Powertrain Control Module Connector End Views)
* Engine Controls Connector End Views (Engine Controls Connector End 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
Circuit/System Verification
1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0115, P0117, P0118, P0120, P0122, or P0123 are not set.
• If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
2. Ignition OFF, remove the fuel tank filler cap.
Important: The FTP sensor reading will vary slightly with atmospheric pressure. The values indicated are for pressures at sea level.
3. Ignition ON, observe that the FTP sensor scan tool parameter is between 3.5-3.8 volts.
4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the EVAP canister assembly.
2. Ignition OFF, test for 5 ohms or less of resistance between the low reference circuit terminal 4 and ground.
• If greater than the specified range, test the low reference circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the PCM.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground.
• If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the PCM.
• If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the PCM.
4. Observe that the FTP sensor scan tool parameter is 5.0 volts.
• If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the PCM.
• If greater than the specified range, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the PCM.
5. Install a 3A fused jumper wire between ground and the FTP sensor signal circuit terminal 3. Verify the FTP sensor scan tool parameter is less than 0.1 volt.
• If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the PCM.
6. If all circuits test normal, replace the FTP sensor located in the EVAP vacuum leak pump assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Evaporative Emission System Vacuum Leak Pump Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for PCM replacement, setup, and programming