Mazda CX-9 Grand Touring 2009 Manual page 1332

POSSIBLE CAUSE
DIAGNOSTIC PROCEDURE
NO.7 SLOW RETURN TO IDLE (MZI-3.7) DIAGNOSTIC PROCEDURE
STEP INSPECTION
Connect the M-MDS to the DLC-2.
Turn the ignition switch to the ON
1 position (Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?
Remove thermostat and inspect operation.
(See THERMOSTAT
REMOVAL/INSTALLATION [MZI-
2 3.7] .)
(See THERMOSTAT INSPECTION
[MZI-3.7] .)
Is thermostat normal?
3 Is throttle body free of contamination?
Verify test results.
If normal, return to diagnostic index to service any additional symptoms.
(See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].)
If malfunction remains, inspect related Service Bulletins and/or On-line Repair
4
Information and perform repair or diagnosis.
2008 Mazda CX-9 Grand Touring
2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
Thermostat is stuck open.
Throttle body malfunction
Air leakage from intake-air system
RESULTS
No
No
No
If vehicle is repaired, troubleshooting completed.
If vehicle is not repaired or additional diagnostic information is not available,
replace the PCM.
(See PCM REMOVAL/INSTALLATION [MZI-3.7] .)
DTC is displayed:
Yes Go to the appropriate DTC inspection.
(See DTC TABLE [MZI-3.7] .)
No DTC is displayed:
Go to the next step.
ECT and thermostat are normal.
Yes
Go to the next step.
Access ECT PID on the M-MDS.
Inspect for both ECT PID and temperature
gauge on instrument cluster readings.
If temperature gauge on instrument cluster
indicates normal range but ECT PID is not
same as temperature gauge reading, inspect
If temperature gauge on instrument cluster
indicates cold range but ECT PID is normal,
inspect temperature gauge and heat gauge
Inspect for air leakage from the intake-air
Yes system components while racing the engine
to higher speed.
Clean or replace throttle body.
ACTION
CHT sensor.
unit.