Function Explanation (DTC Detection Outline)

• The PCM closes the purge solenoid valve and CV solenoid valve while the vehicle is being driven and seals the fuel tank. Then, the evaporative gas in the fuel tank is inducted into the intake manifold and the pressure in the fuel tank is decreased by opening the purge solenoid valve, and the pressure change of the fuel tank is measured using the fuel tank pressure sensor. If the pressure in the fuel tank decreases below the target negative pressure for the specified period from the pressure measurement, the PCM determines that abnormal negative pressure in the fuel tank is being generated and stores a DTC.

Fig 1: DTC Detection Outline Timing Graph

Courtesy of MAZDA MOTORS CORP.