P0496
DTC P0496
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 Descriptor
DTC P0496
- Evaporative Emissions (EVAP) System Continuous Purge Flow
Circuit Description
This DTC tests for continuous intake manifold vacuum flow to the Evaporative Emission (EVAP) System. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Closed. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is greater than a predetermined value within a predetermined time, this DTC sets.
Conditions for Running the DTC
* Before the engine control module (ECM) can report DTC P0496 failed, DTCs P0451, P0452, and P0453 must run and pass.
* DTC P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0125, P0443, P0446, P0449, P0451, P0452, P0453, P0458, P0459, P0496, P0498, P0499, P0560, P0562, P0563, P0700, P2122, P2123, P2127, P2128, P2138, P2227, P2228, or P2229 is not set.
* The fuel system is in closed loop.
* The engine run time is greater than 16 minutes or the long term fuel trim is stable.
* The vehicle speed sensor (VSS) is less than 3 km/h (2 mph).
* The engine is idling.
* The ignition voltage is between 10-18 volts.
* The FTP is between -18.7 to +7.5 mm Hg (-10.0 to +4.0 in H2O).
* The ambient air temperature is between 2-32°C (36-90°F).
* The start-up engine coolant temperature (ECT) is within 10°C (18°F) of ambient air temperature
* The fuel tank level is between 12-88 percent.
* The volumetric efficiency is less than 35 percent.
* The barometric pressure (BARO) is greater than 68 kPa.
* The above conditions are met for greater than 4 seconds.
* DTC P0496 will attempt to run up to 10 times or the test completes successfully once per ignition cycle.
Conditions for Setting the DTC
* The control module detects vacuum during a non-purge condition.
* The condition exists for greater than 4 seconds or for a cumulative of 50 seconds.
Action Taken When the DTC Sets
DTC P0496 is a Type A/B DTC.
Conditions for Clearing the DTC
DTC P0496 is a Type A/B DTC.
Diagnostic Aids
* Observe the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set . This may assist in diagnosing the condition.
* The EVAP system tests run when engine is first started and meets The Conditions for Running the DTC. An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge solenoid valve , or by a temporary blockage or restriction in the EVAP canister purge solenoid valve.
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)
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 Testing
1. Disconnect the EVAP purge solenoid valve electrical harness connector.
2. Start the engine.
3. Command the EVAP vent closed.
4. Increase the engine speed to 1,200-1,500 RPM.
5. Observe the fuel tank pressure sensor inches H2O with a scan tool.
6. Verify the scan tool FTP sensor H2O parameter is -0.5 to +0.5 inches H2O.
• If the FTP sensor in H2O parameter is greater than the specified range, replace the EVAP purge solenoid valve.
7. With the engine OFF and the ignition ON, disconnect the EVAP purge solenoid valve pipe.
8. Observe the FTP sensor in H2O parameter with a scan tool.
9. Verify the FTP sensor is -0.5 to +0.5 inches H2O.
• If the FTP sensor parameter is greater than the specified range, replace the FTP sensor.
Repair Instructions
* Evaporative Emission Canister Purge Solenoid Valve Replacement (Service and Repair)
* Fuel Tank Pressure Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for engine control module replacement, setup, and programming
Repair Verification
1. Start the engine.
2. Command the EVAP vent solenoid closed with a scan tool.
3. Increase the engine idle to 1,200-1,500 RPM.
4. Observe the FTP sensor in H2O parameter with a scan tool.
5. Verify the FTP sensor parameter is -0.5 to +0.5 inches H2O.
6. Clear the DTCs with a scan tool.