Technician A says the EVAP monitor for an OBD-II system determines whether there is sufficient purge flow by varying the purge solenoid duty cycle while monitoring change in STFT. Technician B says the canister vent solenoid must be open during the EVAP pressure test portion of the monitor. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Question

Quizplus · Accepted Answer

Technician A is correct because the EVAP monitor checks for sufficient purge flow by varying the purge solenoid duty cycle and observing changes in the Short Term Fuel Trim (STFT). Technician B is incorrect because the canister vent solenoid should be closed during the EVAP pressure test to seal the system and check for leaks.

Technician a Says the EVAP Monitor for an OBD-II System