NO.7 SLOW RETURN TO IDLE [MZR 1.3, MZR 1.5]

id0103d7801300

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 suction to intake-air system

•  Throttle body contamination

•  PCM malfunction

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 suction to intake-air system • Throttle body contamination • PCM malfunction

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM DTC • Perform the PCM DTC inspection using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.3, MZR 1.5].) • Are any continuous memory DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZR 1.3, MZR 1.5].)
1		No	Go to the next step.
2	INSPECT IF MALFUNCTION CAUSE IS THERMOSTAT OR OTHER • Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.3, MZR 1.5].) • Start the engine and warm it up to ECT PID is above 90 °C {194 °F}. • Does the ECT PID slowly increase at thermostat initial opening temperature? ― Thermostat initial opening temperature: • 80—84 °C {176—183 °F}	Yes	Thermostat operation is normal: • Go to Step 4.
2		No	Go to the next step.
3	INSPECT THERMOSTAT • Cool down the engine. • Remove the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].) • Inspect the thermostat. (See THERMOSTAT INSPECTION [MZR 1.3, MZR 1.5].) • Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].)
3		No	Replace the ECT sensor, if necessary. (characteristic of the ECT sensor malfunction) (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].)
4	INSPECT IF MALFUNCTION CAUSE IS INTAKE-AIR SYSTEM OR THROTTLE VALVE • Visually inspect the throttle body. • Is the throttle body free of contaminations?	Yes	Inspect for air suction to the intake-air system components while racing the engine to higher speed. Repair or replace the malfunctioning part according to the inspection results.
4		No	Clean or replace the throttle body. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].)
5	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 1.3, MZR 1.5].) • If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis. ― If the vehicle is repaired, troubleshooting is completed. ― If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].)