Mazda CX-9 Grand Touring 2009 Manual page 1406

Fig. 16: Stage 1 Test For Large Leak Or Blockage
Courtesy of MAZDA MOTORS CORP.
When fuel tank pressure arrived at the targeted pressure at stage 1 test, M-MDS send the
stage 2 test signal to the PCM to turn off the purge solenoid to keep the tank pressure.
M-MDS detect the small leak if the tank pressure can not keep within the target in specified
period.
Stage 3 test. (Test for blockage)
Fig. 17: Stage 2 Test For Small Leak
Courtesy of MAZDA MOTORS CORP.
M-MDS send the stage 3 test signal to the PCM to turn off the CV solenoid for check the
blockage of EVAP system.
M-MDS detect blockage of the CV solenoid valve or air filter if the tank pressure does not
arrive at the target (atmosphere).
Fig. 18: Stage 3 Test For Blockage
Courtesy of MAZDA MOTORS CORP.
EVAP system malfunction judgment
M-MDS detect the small / large leak or blockage based on fuel tank pressure at the end of EVAP Test.
The EVAP Test could not obtain the target vacuum. A large leak or blockage is suspect.
2008 Mazda CX-9 Grand Touring
2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9