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DTC P0496

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 (EVAP) System Flow During Non-Purge

Circuit/System Description

This DTC tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The engine control module (ECM) seals the EVAP system by commanding the EVAP canister purge solenoid valve OFF and the EVAP canister vent solenoid valve ON. The ECM monitors the fuel tank pressure 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 P0106, P0107, P0108, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P0464, P0608, P0609, P0641, P0651, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138 are not set.

• The ignition voltage is between 11-18 volts.

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

• The fuel level is between 15-85 percent.

• The engine coolant temperature (ECT) at start-up is less than 35°C (95°F).

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

• DTC P0496 runs once per cold start when the above conditions are met.


Conditions for Setting the DTC

The ECM detects more than 10 inch H2O vacuum for 5 seconds during a non-purge condition.

Action Taken When the DTC Sets

DTC P0496 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P0496 is a Type B DTC.

Reference Information

Schematic Reference

Engine Controls Schematics (3.0L (LF1)) Engine Controls Schematics (2.8L (LAU))

Connector End View Reference

Component Connector End Views

Description and Operation

Evaporative Emission Control System Description

Electrical Information Reference


• Circuit Testing

• Testing for Intermittent Conditions and Poor Connections

• Troubleshooting with a Test Lamp

• Wiring Repairs


DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification


1. Ignition ON, engine OFF, seal the EVAP system using the Purge/Seal function with a scan tool.

2. Start the engine.

3. Observe the fuel tank pressure sensor with a scan tool. The Fuel Tank Pressure Sensor parameter should be less than 1.7 volts after 90 seconds.

4. If the Fuel Tank Pressure Sensor parameter is greater than the specified range, go to Circuit/System Testing.

5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.


Circuit/System Testing


1. Ignition ON, engine OFF.

2. Seal the EVAP system using the Purge/Seal function with a scan tool.

3. Start the engine.

4. Observe the fuel tank pressure sensor with a scan tool. The Fuel Tank Pressure Sensor parameter should be less than 1.7 volts after 90 seconds.

5. If the Fuel Tank Pressure Sensor parameter is greater than the specified range, replace the Q12 EVAP canister purge solenoid valve.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Evaporative Emission Canister Purge Solenoid Valve Replacement (LAU) Evaporative Emission Canister Purge Solenoid Valve Replacement (LF1)