NO.7 SLOW RETURN TO IDLE [ZJ, ZY]

id0103b0801300

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

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/KOER self test. (See KOEO/KOER SELF TEST [ZJ, ZY].) Are any continuous memory DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [ZJ, ZY].)
1		No	Go to the next step.
2	Remove the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [ZJ, ZY].) Inspect the thermostat. (See THERMOSTAT INSPECTION [ZJ, ZY].) Is there any malfunction?	Yes	Go to the next step.
2		No	Go to Step 4.
3	Perform the PID/DATA Monitor and Record Procedure and access the ECT PID. (See ON-BOARD DIAGNOSTIC TEST [ZJ, ZY].) Inspect for both ECT PID and temperature gauge on the instrument cluster readings. Does the temperature gauge on the instrument cluster indicate normal range but the ECT PID is not same as temperature gauge reading?	Yes	Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [ZJ, ZY].) Replace the ECT sensor, if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [ZJ, ZY].)
3		No	If the temperature gauge on the instrument cluster indicates cold range but the ECT PID is normal: • Inspect the temperature gauge and the heat gauge unit. • Repair or replace the malfunctioning part according to the inspection results.
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.
4		No	Clean or replace the throttle body. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [ZJ, ZY].)
5	Verify test results. • If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [ZJ, ZY].) • If malfunction remains, inspect related Service information perform repair or diagnosis ― f vehicle repaired, troubleshooting completed. ― If vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [ZJ, ZY].)