Home

Mazdamanuals.com

 NO.9 FAST IDLE/RUNS ON [L8, LF, L3]

NO.9 FAST IDLE/RUNS ON [L8, LF, L3]

id0103a1801500

9

FAST IDLE/RUNS ON

DESCRIPTION

• The engine speed continues at fast idle after warm-up.
• The engine runs after the ignition switch is turned off.

POSSIBLE CAUSE

• ECT sensor malfunction
• Air leakage from intake-air system
• Throttle body malfunction
• Accelerator pedal position sensor misadjustment
• Cruise control system operation improperly
• Improper load signal input
• Improper operation of electronic throttle control system

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1
Connect the WDS or equivalent 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 WDS or equivalent 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.
No

No DTC is displayed:

Go to the next step.
3
Connect the WDS or equivalent to DLC-2
Access ACSW, COLP, CPP/PNP, TR and PSP PIDs.
Monitor each PID.
Are PIDs value okay?
Yes
Go to the next step.
No

ACSW PID is not specified: Inspect A/C switch, refrigerant pressure switch and fan switch.

COLP PID is not specified: Inspect refrigerant

pressure switch (middle pressure).

CPP PID is not specified: Inspect clutch switch (MTX).

CPP/PNP PID: Inspect neutral switch (MTX).

TR PID: TR switch (ATX).

PSP PID: Inspect P/S pressure switch.

4
Is there air leakage felt or heard at intake-air system components while racing engine to higher speed?
Yes
Repair or replace parts if necessary.
No
Inspect the following:
• Electronic throttle control system operation
• Accelerator pedal position sensor
5
• Verify test results.
- If normal, return to diagnostic index to service any additional symptoms.
(See ENGINE SYMPTOM TROUBLESHOOTING [L8, LF, L3].)
- If malfunction remains, inspect related Service Information and perform repair or diagnosis.
• 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 [L8, LF, L3].)