NO.7 SLOW RETURN TO IDLE[AJ (3.0L Duratec)]

id0103a7801300

7
Slow return to idle
DESCRIPTION
•  The 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.
•  Turn the ignition switch to the ON position (Engine off).
•  Retrieve any DTCs.
•  Is “PASSED” displayed?
Yes
No DTC is displayed:
•  Go to the next step.
No
DTC is displayed:
•  Go to the appropriate DTC test.
2
•  Remove the thermostat and inspect operation.
•  Is the thermostat normal?
Yes
ECT and thermostat are normal.
Go to the next step.
No
Access the ECT PID.
Inspect for both ECT PID and temperature gauge on instrument cluster readings.
•  If the temperature gauge on instrument cluster indicates normal range but ECT PID is not same as temperature gauge reading, inspect ECT sensor.
•  If the temperature gauge on instrument cluster indicates cold range but ECT PID is normal, inspect temperature gauge and heat gauge unit.
3
•  Is the throttle body free of contaminations?
Yes
Inspect for air leakage from intake-air system components while racing engine to higher speed.
No
Clean or replace the throttle body.
4
•  Verify the test results.
―  If normal, return to the diagnostic index to service any additional symptoms.
―  If malfunction remains, inspect related Service Information and perform repair or diagnosis.
•  If vehicle is repaired, troubleshooting completed.
•  If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.