NO.7 SLOW RETURN TO IDLE [L8, LF, L5]

id010346801300

7

SLOW RETURN TO IDLE

DESCRIPTION

Engine takes more time than normal to return to idle speed.

POSSIBLE CAUSE

•  ECT sensor malfunction

•  Thermostat is stuck open.

•  Throttle body malfunction

•  Air leakage from intake air system

7	SLOW RETURN TO IDLE
DESCRIPTION	Engine takes more time than normal to return to idle speed.
POSSIBLE CAUSE	• ECT sensor malfunction • Thermostat is stuck open. • Throttle body malfunction • Air leakage from intake air system

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	Connect the M-MDS to the DLC-2. Switch the ignition to ON (Engine off). Retrieve any DTCs. Are there any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC inspection. (See DTC TABLE [L8, LF, L5].)
1		No	No DTC is displayed: Go to the next step.
2	Remove thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [L8, LF, L5].) (See THERMOSTAT INSPECTION [L8, LF, L5].) Is thermostat normal?	Yes	ECT and thermostat are normal. Go to the next step.
2		No	Access the ECT PID on the M-MDS. Inspect both the ECT PID and temperature gauge on instrument cluster readings. If the temperature gauge on instrument cluster indicates a normal range but the ECT PID is not the same as the temperature gauge reading, inspect the ECT sensor. If the temperature gauge on the instrument cluster indicates a cold range but the ECT PID is normal, inspect the temperature gauge and heat gauge unit.
3	Is the throttle body free of contamination?	Yes	Inspect for air leakage from the intake air system components while racing the engine to higher speed.
3	Is the throttle body free of contamination?	No	Clean or replace throttle body.
4	• Verify test results. ― If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [L8, LF, L5].) ― If a malfunction remains, inspect the related Service Information and perform 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 [L8, LF, L5].)