For 1990-2009 cars

### 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

### Diagnostic Fault Information

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

### 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 (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.

### Conditions for Running the DTC

• | DTCs P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0128, P0442, P0443, P0446, P0449, P0452, P0453, P0502, P0503 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 start-up engine coolant temperature (ECT) is less than 35°C (95°F).

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

• | The start-up ECT and IAT are within 8°C (14.4°F) of each other.

• | The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

• | DTC P0496 runs once per cold start within 17 minutes.

### Conditions for Setting the DTC

• | The ECM detects vacuum during a non-purge condition.

• | The fuel tank vacuum is greater than 10 inches H2O for 5 seconds within 60 seconds of cold start.

### 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

• | Evaporative Emissions Hose Routing Diagram

#### Connector End View Reference

Component Connector End Views

#### 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 Testing

1. Start the engine.
2. Seal the EVAP system using the Purge/Seal function with a scan tool.
3. 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 the 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