Checking and adjusting idle speed / ignition timing / CO concentration (Mercedes-Benz M-Class W163)

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

The reason for deviation of actual parameters from nominal values may be a malfunction of components that should be replaced. Qualified check of the control system requires the use of special diagnostic devices.

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