NO.7 SLOW RETURN TO IDLE [ZY, Z6]

id0103b9801300

7

SLOW RETURN TO IDLE
DESCRIPTION
The engine takes more time than normal to return to the 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 WDS or equivalent to the DLC-2.
Retrieve any continuous memory, KOEO and KOER DTCs using WDS or equivalent.
Are there DTCs displayed?
Yes
DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE [ZY, Z6].)
No
No DTC is displayed:
Go to the next step.
2
Remove the thermostat and inspect operation.
(See THERMOSTAT REMOVAL/INSTALLATION [ZY, Z6].)
(See THERMOSTAT INSPECTION [ZY, Z6].)
Is the thermostat normal?
Yes
The ECT sensor and thermostat are normal.
Go to the next step.
No
Access ECT PID on WDS or equivalent.
Inspect for both ECT PID and temperature gauge on the instrument cluster readings.
•  If the temperature gauge on the instrument cluster indicates normal range but ECT PID is not same as temperature gauge reading, inspect the ECT sensor.
•  If the temperature gauge on the instrument cluster indicates cold range but ECT PID is normal, inspect the temperature gauge and the heat gauge unit.
3
Is the throttle body free of contaminations?
Yes
Inspect for air leakage from intake-air system components while racing the engine to higher speed.
No
Clean or replace the throttle body.
4
Verify test results.
•  If normal, return to diagnostic index to service any additional symptoms.
•  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.