DIAGNOSTIC PROCEDURE
NO.7 SLOW RETURN TO IDLE (MZI-3.7) DIAGNOSTIC PROCEDURE
POSSIBLE CAUSE
z
Thermostat is stuck open.
z
Throttle body malfunction
z
Air leakage from intake-air system
STEP
INSPECTION
RESULTS
ACTION
1
Connect the M-MDS to the DLC-2.
Turn the ignition switch to the ON
position (Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?
Yes
DTC is displayed:
Go to the appropriate DTC inspection.
(See
DTC TABLE [MZI-3.7]
.)
No
No DTC is displayed:
Go to the next step.
2
Remove thermostat and inspect operation.
(See
THERMOSTAT
REMOVAL/INSTALLATION [MZI-
3.7]
.)
(See
THERMOSTAT INSPECTION
[MZI-3.7]
.)
Is thermostat normal?
Yes
ECT and thermostat are normal.
Go to the next step.
No
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
CHT sensor.
If temperature gauge on instrument cluster
indicates cold range but ECT PID is normal,
inspect temperature gauge and heat gauge
unit.
3
Is throttle body free of contamination?
Yes
Inspect for air leakage from the intake-air
system components while racing the engine
to higher speed.
No
Clean or replace throttle body.
4
z
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
Information and perform repair or diagnosis.
z
If vehicle is repaired, troubleshooting completed.
z
If vehicle is not repaired or additional diagnostic information is not available,
replace the PCM.
(See
PCM REMOVAL/INSTALLATION [MZI-3.7]
.)
2008 Mazda CX-9 Grand Touring
2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
Microsoft
Sunday, November 15, 2009 10:10:05 AM
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© 2005 Mitchell Repair Information Company, LLC.
