NO.7 SLOW RETURN TO IDLE[LF, L3]

id0103b2801300

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.
Retrieve any continuous memory, KOEO and KOER DTCs using M-MDS.
Are there DTCs displayed?
Yes
DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE[MTX, LF ATX (FS5A-EL)].)
(See DTC TABLE[LF ATX (FN4A-EL), L3 ATX].)
No
No DTC is displayed:
Go to the next step.
2
Remove thermostat and inspect operation.
(See THERMOSTAT REMOVAL/INSTALLATION[LF, L3].)
(See THERMOSTAT INSPECTION[LF, L3].)
Is thermostat normal?
Yes
ECT sensor and thermostat are normal.
Go to the next step.
No
Access ECT PID on the M-MDS.
Inspect for both ECT PID and temperature gauge on instrument cluster readings.
•  If temperature gauge on instrument cluster indicates normal range but ECT PID is not same as temperature gauge reading, inspect ECT sensor.
•  If temperature gauge on instrument cluster indicates cold range but ECT PID is normal, inspect temperature gauge and heat gauge unit.
3
Is throttle body free of contaminations?
Yes
Inspect for air leakage from the intake-air system components while racing 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.