What Causes High Idle Speed in Sedans?

1 Answers
RowanLee
07/30/25 7:15am
The reasons for high idle speed in sedans include: throttle valve sticking, idle control valve failure, coolant temperature sensor failure, intake system air leakage, air conditioning switch failure, and power steering pressure switch failure. Idle control valve failure: The normal idle speed of an electronically fuel-injected engine is determined by the idle control valve. If oil contamination or carbon buildup causes the idle control valve to stick or the throttle valve to not close properly, the electronic control unit (ECU) cannot accurately adjust the engine's idle speed. Intake system air leakage: Under normal circumstances, the intake air volume must be strictly controlled. If there is a leak in the intake pipe, the air flow sensor cannot measure the actual intake air volume, leading to inaccurate control of the intake air by the ECU and resulting in unstable idle speed.
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