P0499

DTC P0499: Evaporative Emission (EVAP) Vent Solenoid Control Circuit High Voltage

Wiring Diagram:

Circuit Description
The Evaporative emission (EVAP) canister vent valve is used for EVAP system diagnostics. The EVAP canister vent valve is a normally open valve. Battery positive voltage is supplied directly to the EVAP canister vent 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.

Conditions for Setting the DTC
- Engine is running.
- Battery voltage is between 11 and 16 V.
- An open in the EVAP vent solenoid circuit exists.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- The MIL will turn OFF after four consecutive validation cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- The DTC(s) can be cleared by using the scan tool.

Diagnostic Aids
If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The ODM information is in the output driver module (ODM) data list. For an intermittent condition, refer to Intermittents Intermittents.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. This step determines if a condition exists. An audible click should be heard when the EVAP canister vent valve is commanded ON and OFF. Repeat the commands as necessary.

Step 1-9:

Step 10-11:

Troubleshooting