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 P0498 00: Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit Low Voltage
DTC P0499 00: Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition Voltage | P0499 00 | P0498 00 | -- | --
EVAP Canister Vent Solenoid Valve Control Circuit | P0498 00 | -- | P0499 00 | --

### Circuit/System Description

The evaporative emission (EVAP) canister vent valve is used for EVAP system diagnostics. The EVAP canister vent solenoid valve is a normally open valve. Battery positive voltage is supplied directly to the EVAP canister vent solenoid valve. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM detects the control circuit voltage is within a predetermined range when the circuit is commanded OFF, this DTC sets.

### Conditions for Running the DTC

• | The engine speed is greater than 80 RPM.

• | The ignition voltage is between 10-18 V.

• | The ECM has commanded the EVAP canister vent solenoid valve ON and OFF at least once during the ignition cycle.

• | DTCs P0498 00 or P0499 00 run continuously once the above conditions are met.

### Conditions for Setting the DTC

#### P0498 00

The ECM detects the voltage on the EVAP canister vent solenoid valve control circuit is less than 2.6 V when the driver is commanded OFF. The condition is present for greater than 4 s or for a cumulative of 30 s.

#### P0499 00

The ECM detects the voltage on the EVAP canister vent solenoid valve control circuit is greater than 4.6 V when the driver is commanded ON. The condition is present for greater than 4 s or for a cumulative of 30 s.

### Action Taken When the DTC Sets

• | DTC P0498 00 and P0499 00 are Type B DTCs.

• | The EVAP system will only purge during open loop.

### Conditions for Clearing the DTC

DTC P0498 00 and P0499 00 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Evaporative Emission Control System Description

#### 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

### Circuit/System Verification

1. Command the EVAP vent solenoid valve ON and OFF with the scan tool. An audible click should be heard when changing between the commanded states.
2. Start the engine, observe the DTC information with a scan tool. DTC P0498 00, or P0499 00 should not set.
3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

### Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid Valve.
2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal 1 and ground.

⇒ | If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid Valve.

3. Ignition OFF, test for more than 500 kΩ between the control circuit terminal 2 and ground.

⇒ | If less than the specified range, repair the short to ground. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

Note: The control circuit for the EVAP vent solenoid valve is pulled-up to voltage within the K20 Engine Control Module (ECM), 2.6-4.6 V on the control circuit is normal.

4. Ignition OFF, test for less than 0.3 V between the control circuit terminal 2 and ground.

⇒ | If more than the specified range, repair the short to B+. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

5. Ignition OFF, disconnect the K20 Engine Control Module (ECM) X2 connector. Test for less than 5 Ω between the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid connector terminal 2 and the K20 Engine Control Module (ECM) terminal 72 (X2).

⇒ | If more than the specified range, repair the open circuit. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

### Component Testing

#### Static Test

1. Test for 20-24 Ω between the terminals of the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid Valve.

⇒ | If not within the specified range, replace the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid Valve.

2. Test for infinite resistance between each terminal of the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid Valve and the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid Valve housing.

⇒ | If not within the specified value, replace the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid Valve.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | LINK (Evaporative Emission Canister Vent Solenoid Valve Replacement)

• | Control Module References for ECM replacement, setup, and programming