NO.7 SLOW RETURN TO IDLE [MZR 1.6]


id0103f9801300

7

SLOW RETURN TO IDLE

DESCRIPTION
•  The engine takes more time than normal to return to idle speed.
POSSIBLE CAUSE
•  Continuous memory DTC is stored
•  Thermostat malfunction (stuck open)
•  ECT sensor malfunction
•  Air leakage from intake-air system
•  Throttle body contamination
•  PCM malfunction

Diagnostic Procedure

STEP

INSPECTION

ACTION

1
Connect the M-MDS to the DLC-2.
Perform the KOEO or KOER self test.
Are any continuous memory DTCs present?
Yes
Go to the appropriate DTC inspection.
No
Go to the next step.
2
Access the ECT PID using the M-MDS.
Start the engine and warm it up to ECT PID is above 90 °C {194 °F}.
Does the ECT PID increasing dull at thermostat initial opening temperature?
Thermostat initial opening temperature
•  80—84 °C {176—183 °F}
Yes
Go to Step 4.
No
Go to the next step.
3
Remove the thermostat.
Inspect the thermostat.
Is there any malfunction?
Yes
Replace the thermostat.
No
Inspect the characteristic of the ECT sensor.
Replace the ECT sensor, if necessary.
4
Visually inspect the throttle body.
Is the throttle body free of contaminations?
Yes
Inspect for air leakage from intake-air system components while racing the engine to higher speed.
Repair or replace the malfunctioning part according to the inspection results.
No
Clean or replace the throttle body.
5
Verify the test results.
•  If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 1.6].)
•  If malfunction remains, inspect related Service information perform repair or diagnosis
―  If vehicle repaired, troubleshooting completed.
―  If vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 1.6].)