Why does Audi a4 idle speed control exceed the specified value?

The fault that the idle speed exceeds the specified value is because the throttle is dirty, and the computer corrects the throttle opening in real time. When the throttle valve is dirty to a certain extent and the correction amount reaches the limit, the computer will report this fault code, so it is necessary to clean the throttle valve and check whether the intake pipe leaks.

When the idle speed of automobile engine is lower than or exceeds the specified range, staged flameout and unstable speed will occur. Idle instability is characterized by engine jitter and uneven speed at idle speed, which is caused by the blockage of idle air holes, poor idle device, weak spark of spark plugs in individual cylinders, lax seal of individual valves, air leakage in intake manifold, early or late ignition time, improper idle speed adjustment, etc.

If the speed is unstable, adjust the idle speed first. If the fault cannot be eliminated after adjustment, check whether the idle hole and idle air circulation hole are blocked. If the measuring hole is blocked, it can be cleaned with gasoline or acetone and purged with compressed air. If the measuring hole is not blocked, stabilize the engine speed at a certain speed and listen to whether the intake manifold or the lower gasket of carburetor leaks. If air leakage occurs, it can be eliminated by tightening screws or increasing or decreasing gaskets.

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