A Mercedes-Benz 560SEL car replacement battery after idle at 2000r / min high.
    Troubleshooting
    With the pliers to clamp the idle bypass hose, idle down, and then tighten the idle speed is still down and running smoothly, indicating that the idle valve opening is too large. Remove the idle valve hose (idle line is still inserted), hand blocked to the intake manifold side of the hose (leaving a gap) with the car to observe the action of the idle valve, when the gap size changes when the idle Change, but the idle valve is always in the open maximum position, indicating that there is a problem with idling control.
    The idle valve opening degree is controlled by the 12-foot idling control module. Open the ignition switch to check the terminals (6, 7 feet signal output to the idle valve, the rest are input signal pin), found that there is an overvoltage protection relay input pin is 0V (the rest of the pins have a signal), further check Found that the 10A fuse fuse has been burned, replaced with other components installed after the car all normal.
    cause of issue
    Idle control computer has not received overvoltage protection relay signal leaving the output current is not normal, so that the idle valve open too large cause high idle speed. Owners to replace the battery method is wrong to cause lOA insurance blown.