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 P0497: Evaporative Emission System Low Purge Flow

### Circuit/System Description

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

This DTC tests for proper intake manifold vacuum flow to the evaporative emission (EVAP) system. The engine control module (ECM) opens the EVAP canister purge solenoid valve and closes the EVAP canister vent solenoid valve. The ECM then 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 less than a predetermined value within a predetermined time, this DTC sets. The preceding 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 P0030, P0031, P0032, P0053, P0100, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0114, P0117, P0118, P0119, P0122, P0123, P0128, P0130, P0131, P0132, P0133, P0135, P0221, P0222, P0223, P0443, P0449, P0450, P0451, P0452, P0453, P0458, P0459, P0498, P0499, P0501, P0502, P167A, P2122, P2123, P2127, P2128, P2138, P2177, P2178, P2187, P2188, P2195, P2196, P2199, P2227, P2228, P2229, P2237, P2243, P2251, P2297, P2626 are not set.

• | The ignition voltage is between 11-18 volts.

• | The barometric pressure (BARO) is more than 68 kPa.

• | The fuel level is between 15-85 percent.

• | The fuel tank pressure is between -2.5 and +1.3 kPa (-10 and +5 in H2O).

• | The engine coolant temperature (ECT) is between 4-30°C (39-86°F).

• | The intake air temperature is between 2-32°C (35.6-90°F).

• | The start-up ECT and IAT are within 9°C (14.4°F) of each other.

• | The vehicle speed sensor (VSS) is less than 1.7 km/h (2 mph).

• | DTC P0497 will attempt to run up to 10 times until it successfully completes.

• | DTC P0497 completes one test per cold start within 10 minutes of start-up.

### Conditions for Setting the DTC

• | The ECM detects weak vacuum during a purge condition.

• | The fuel tank vacuum is less than -1 inches H2O for 4 seconds continuously or 50 seconds cumulative, within 10 minutes of cold start.

• | The 11 second test can run up to 10 times within 10 minutes of cold start and must be completed before this DTC will set.

### Action Taken When the DTC Sets

DTCs P0497 is a Type B DTC.

### Conditions for Clearing the MIL/DTC

DTCs P0497 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

• | Connector Repairs

• | 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

#### Special Tools

• | GE-41415-50 Fuel Tank Cap Adapter

• | J 41413-311 EVAP Plug

• | J 41413-200 (J 41413-100) Evaporative Emission System Tester (EEST)

### Circuit/System Verification

Note: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Refer to J 41413-200 (J 41413-100) operation manual for detailed instructions in Evaporative Emission System Diagnosis.

1. Connect the J 41413-200 nitrogen/smoke hose to the J 41413-311 brass cone adapter. Disconnect the hose at the fuel cap end of the GE-41415-50 . Connect the J 41413-311 to the disconnected hose on the GE-41415-50 . Install the GE-41415-50 filler neck end only to the vehicle.
2. Seal the system with a scan tool and use the flow meter on the J 41413-200 (J 41413-100) calibrated to 0.51 mm (0.020 in) to determine there is no leak in the EVAP system.

⇒ | If a leak is detected, use the J 41413-200 (J 41413-100) to apply smoke to the EVAP system at the filler neck until the leak is located.

### Circuit/System Testing

Important: Perform the Circuit/System Verification before proceeding with the Circuit/System Testing.

1. Start the engine.
2. Seal the EVAP system using the Purge/Seal function with a scan tool.
3. Command the EVAP canister purge solenoid valve to 50 percent.
4. Observe the FTP sensor with a scan tool. The Fuel Tank Pressure Sensor parameter should be more than 2 volts after 60 seconds.

⇒ | If the Fuel Tank Pressure Sensor parameter is less than the specified range, repair the blocked purge path or 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