OBDII evaporative system integrity testing is being discussed. Technician A says the integrity check is done by creating a vacuum in the tank and measuring how well it holds the vacuum. Technician B says the fuel tank pressure (FTP)sensor is a transducer that converts the absolute pressure in the fuel tank into an input for the PCM. Who is correct?

Question

Quizplus · Accepted Answer

Technician A is correct because the evaporative system integrity check often involves creating a vacuum (or pressure difference) in the fuel system and monitoring how well it maintains that condition, which helps in identifying leaks. Technician B is correct because the Fuel Tank Pressure (FTP) sensor does indeed convert the pressure in the fuel tank into a signal that the Powertrain Control Module (PCM) can use to monitor the system's integrity and control emissions.

OBDII Evaporative System Integrity Testing Is Being Discussed