Checking idle speed / ignition timing / CO concentration (Mercedes-Benz C-Class W203)

As part of maintenance, adjustment of idle speed, ignition timing and CO concentration is not required, since these parameters are set by the control system depending on requirements.

If the actual parameters differ from the specified ones, the reason lies in the malfunction of the parts that must be replaced. A qualified check of the control system requires special diagnostic devices.

Note: The idle speed may be slightly changed by reprogramming the control unit using a diagnostic tool.

(Full article available on the resource: «MERCEDESMAN»)