DESCRIPTION AND POSSIBLE CAUSES
DIAGNOSTIC PROCEDURE
DIAGNOSTIC PROCEDURE
9
FAST IDLE/RUNS ON
DESCRIPTION
z
The engine speed continues at fast idle after warm-up.
z
The engine runs after the ignition switch is turned off.
POSSIBLE CAUSE
z
CHT sensor malfunction
z
Air leakage from intake-air system
z
Throttle body malfunction
z
Accelerator pedal position sensor misadjustment
z
Cruise control system operation improperly
z
Improper load signal input
z
Improper operation of electronic throttle control system
STEP INSPECTION
RESULTS ACTION
1
Connect the M-MDS to the DLC-2.
Access ECT PID.
Start and warm up engine to normal
operating temperature.
Is ECT PID between
82-112°C {180-
234°F}?
Yes
Go to the next step.
No
ECT PID is higher than 112°C
{234°F}:
Go to symptom troubleshooting
"No.17 Cooling system concerns -
Overheating".
ECT PID is less than 82°C {180°F}:
Go to symptom troubleshooting
"No.18 Cooling system concerns -
Runs cold".
2
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-3.5]
.)
No
No DTC is displayed:
Go to the next step.
3
Access and monitor PSP and TR PIDs.
Are PIDs values normal?
(see
PCM INSPECTION [MZI-3.5]
.)
Yes
Go to the next step.
No
If the AC_REQ PID is not normal:
z
Inspect A/C switch, refrigerant
pressure switch, and fan switch,
and related wiring harness for
vibration or intermittent
open/short circuit.
2007 Mazda CX-9 Grand Touring
2007 ENGINE PERFORMANCE Symptom Troubleshooting (MZI-3.5) - CX-9
Microsoft
Sunday, November 15, 2009 9:27:37 AM
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