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NO.7 SLOW RETURN TO IDLE [L3]

BME010300000W09

7 | SLOW RETURN TO IDLE
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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
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1 | Connect WDS or equivalent to DLC-2. Retrieve any continuous memory, KOEO and KOER DTCs. Are there DTCs displayed? | Yes | DTC is displayed: Go to appropriate DTC test.
No | No DTC is displayed: Go to next step.
2 | Remove thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [L3].) (See THERMOSTAT INSPECTION.) Is thermostat okay? | Yes | ECT and thermostat are okay. Go to next step.
No | Access ECT PID on WDS or equivalent. 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 intake-air system components while racing engine to higher speed.
No | Clean or replace throttle body.
4 | Verify test results. • If okay, return to diagnostic index to service any additional symptoms. • If malfunction remains, replace PCM.