DTC P0496. Buick Lucerne 2009

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2009 🢒 Lucerne 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC P0496

Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0496: Evaporative Emission System Flow During Non-Purge

This DTC tests for undesired 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 OFF and the EVAP canister vent solenoid valve ON. 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 more than a predetermined value within a predetermined time, this DTC sets. The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.

Control Module Command	EVAP Canister Purge Solenoid Valve	EVAP Canister Vent Solenoid Valve
ON	Open	Closed
OFF	Closed	Open

Conditions for Running the DTC

•	DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0128, P0442, P0443, P0446, P0449, P0452, P0453, P1516 are not set.

•	The ignition voltage is between 10-18 volts.

•	The barometric pressure (BARO) is more than 74 kPa.

•	The fuel level is between 15-85 percent.

•	The engine coolant temperature (ECT) is less than 30°C (86°F).

•	The start-up IAT is less than 30°C (86°F).

•	The intake air temperature (IAT) is between 4-30°C (39-86°F).

•	The start-up ECT and IAT are within 8°C (14°F) of each other.

•	The FTP sensor is less than -2.5 inches H2O at ignition ON.

•	DTC P0496 runs once per cold start for 96 seconds.

Conditions for Setting the DTC

•	The control module detects vacuum during a non-purge condition.

•	The FTP sensor is more than -10 inches H2O for 60 seconds.

Schematic Reference

•	Engine Controls Schematics

•	Evaporative Emissions Hose Routing Diagram

Connector End View Reference

Component Connector End Views

Electrical Information Reference

•	Circuit Testing

•	Troubleshooting with a Test Lamp

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

Start the engine.
Seal the EVAP system using the Purge/Seal function with a scan tool.
Observe the FTP sensor with a scan tool. The Fuel Tank Pressure Sensor parameter should be less than 1.7 volts after 90 seconds.

⇒	If the Fuel Tank Pressure Sensor parameter is greater than specified range, replace the EVAP canister purge solenoid valve.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Evaporative Emission Canister Purge Solenoid Valve Replacement