What is the fault diagnosis process of automobile idling?

The high idle speed of cars may be caused by many reasons. The following is a possible troubleshooting process:

Check the air filter: Dirty or clogged air filter may cause the engine not to get enough air, which may lead to high idle speed.

Check the throttle: If the throttle is blocked or stuck, it may lead to insufficient air flow, which may lead to high idle speed.

Check the air intake system: Leakage or damage of the air intake system may cause the engine to receive an incorrect air-fuel ratio, which may lead to high idle speed.

Check the throttle position sensor: Failure of the throttle position sensor may cause the engine to receive incorrect information, which may lead to high idle speed.

Check the air-conditioning system: the failure of the air-conditioning compressor may cause the engine to idle too fast.

Check the Electronic Control Module (ECM): A faulty ECM may cause the engine to receive incorrect signals, resulting in excessive idle speed.

Check the throttle motor: Failure of the throttle motor may cause the engine to receive incorrect information, which may lead to high idle speed.

Check the fuel system: Failure of the fuel system may cause the engine to receive an incorrect amount of fuel, resulting in high idle speed.

These are all possible fault diagnosis processes, but the possible faults are different because of the different design and configuration of each car. It is recommended to send the vehicle to a professional automobile maintenance center for comprehensive inspection and diagnosis.