The ECM checks the CCV malfunction by commanding the CCV to open after the EVAP leak test. If the fuel tank pressure does not rise (lose vacuum), the ECM determines that the CCV is stuck closed. The ECM will turn on the MIL and a DTC is set.
If the EVAP VSV "stuck closed" is detected, the ECM determines that the CCV is "stuck open". The ECM will turn on the MIL and a DTC is set.
The ECM checks the pressure switching valve (bypass VSV) "stuck closed" by commanding the pressure switching valve to close after the EVAP leak test. If the fuel tank pressure does not change, the ECM determines that the pressure switching valve is malfunctioning. The ECM will turn on the MIL and a DTC is set.
