Mazda CX-9 Grand Touring. Manual - part 352

EVAPORATIVE EMISSION (EVAP) SYSTEM LEAK INSPECTION



To verify that the problem has been fixed properly after repairs, the run drive cycle or EVAP system leak
inspection must be performed.

EVAP system leak inspection using the M-MDS

EVAP system test out line



The EVAP system test, which can substituted for the run drive cycle as an EVAP control system repair
confirmation method, can detect the small / large leak or blockage without run-drive cycle.

EVAP system test description



The EVAP system test finds gas leaks or blockage of EVAP system using the changes of the fuel tank
pressure.



This test starts after sending an on-demand test signal from the M-MDS to the PCM.



This test consists of three stages, and each stage is performed automatically as follows:

Stage 1 test. (Test for large leak or blockage)



M-MDS send the stage 1 test start signal to the PCM.



PCM controls the CV solenoid valve and purge solenoid valve to control the tank pressure to
the targeted value.



M-MDS detect the large leak or the purge line blockage if the tank pressure does not arrive at
the target vacuum in specified period.

Stage 2 test. (Test for small leak)

NOTE:



Use the IDS (laptop PC) because the PDS (Pocket PC) does not support
the EVAP system test.

NOTE:



M-MDS can not detect "VERY SMALL LEAK". To identify the leak
point, please use the leak tester or ultrasonic leak detector.

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

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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

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

This judgment means tank pressure could not arrive at target pressure at stage 1 test.



Check for the large leakage or inspect the purge solenoid valve operation and related hoses.



Repair or replace any malfunctioning parts.

The EVAP Test could not maintain the target vacuum. A small leak is suspect.



This judgment means tank pressure could not stay in target pressure at stage 2 test.



Run the EVAP Test again after Re-tighten the fuel filler cap.



If small leak is suspected again, use the leak tester or ultrasonic leak detector for identify the leak
point.



Repair or replace any malfunctioning parts.

Blockage in EVAP system.



This judgment means tank pressure could not return to atmosphere at stage 3 test.



Inspect the CV solenoid, Air filter, Charcoal canister and related hoses for blockage.

No large leaks or blockage have been detected in the EVAP system at this time.



M-MDS can not detect "VERY SMALL LEAK".



To identify the leak point, please use the leak tester or ultrasonic leak detector.

Evaporative system test procedure

1. Verify that all PIDs within the following specifications.

2. Select the following items from the initialization screen of the M-MDS.

1. Select the "Powertrain".

2. Select the "Fuel".

3. Select the "EVAP Test".



Verify that ECT and IAT are within the specifications at the confirmation screen. To
successfully perform this procedure, ECT and IAT must be within the spec before proceeding
to the next step.



Fuel Level must be maintained within 15%-85%. PCM will cancel the EVAP Test If the
Fuel Level is lower than 15% or higher than 85%.

NOTE:



To successfully perform this procedure, all PIDs must be within the
specifications before proceeding to the next step.

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Fig. 19: Evaporative System Test Procedure
Courtesy of MAZDA MOTORS CORP.

3. Verify the test results described on the M-MDS and follow the instructions.

EVAP system leak inspection using leak tester

1. Perform the following SST (EVAP System Tester 134-01049) self-test:

1. Verify that the control valve on the panel is in the HOLD position then open the nitrogen bottle

valve.

2. Connect the vehicle interface hose (part of the SST ) to the SELF-TEST port located on the control

panel. Hand tighten the fitting. (Do not overtighten.)

3. Turn the control valve to the TEST position.

4. The gauge should read 331-381 mm {13-15 in} of water.



If the gauge is not reading in this range, adjust the pressure by turning the black knob on the
low pressure regulator at the nitrogen bottle.

5. Turn the control valve to the HOLD position.

6. Verify that the gauge holds pressure and that the flow meter reads no flow.



If there is no drop in pressure and no flow, the tester passes the self-test.



If the gauge leaks down, refer to the tester operators manual.

NOTE:



If the tester does not work correctly during the self-test, refer to the
tester operators manua for a more detailed self-test procedure.

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

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Sunday, November 15, 2009 10:10:06 AM

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