Evaporative Emission Purge Solenoid Valve Leak Test
WARNING: This page is about a different car, the 2022 Cadillac CT5. However, it is still accessible from the selected car via links, so may be relevant.
If the Q12 Evaporative Emission Purge Solenoid Valvedoes not seal properly, fuel vapors could enter the engine at an undesired time, causing driveability concerns. The ECM tests for this by commanding the G58 Evaporative Emission Purge Pump, the Q12 Evaporative Emission Purge Solenoid ValveOFF/Closed and the Q13 Evaporative Emission Canister Vent Solenoid ValveON/Closed which seals the system. With the engine running, the ECM then monitors the B150 Fuel Tank Pressure Sensorfor an increase in vacuum. The ECM will set a DTC if a vacuum develops in the tank under these test conditions.