NO.7 SLOW RETURN TO IDLE [L3]

BME010300103245

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 WDS or equivalent to the DLC-2.
Retrieve any continuous memory, KOEO and KOER DTCs.
Are there DTCs displayed?
Yes

DTC is displayed:

Go to the applicable DTC inspection.
No

No DTC is displayed:

Go to the next step.
2
Remove the thermostat and inspect the operation.
Is the thermostat normal?
Yes
The ECT and the thermostat are normal.
Go to the next step.
No
Access ECT PID on the WDS or equivalent.
Inspect for both ECT PID and temperature gauge on instrument cluster readings.
If the temperature gauge on the instrument cluster indicates normal range but ECT PID is not the same as the 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 the intake-air system components while racing the engine to higher speed.
No
Clean or replace throttle body.
4
Verify test results.
• If normal, return to diagnostic index to service any additional symptoms.
• If malfunction remains, replace PCM.