Information on Catalytic Converter Heating

1. Catalytic converter heating during warm-up

To ensure the catalytic converter is fully effective as fast as possible, the following measures have been introduced for the idle phases after start-up.

• Retarded idle ignition timing (angle)
  
• Change in valve timing to larger intersection
  

These measures are active for approx. one minute after start-up and are designed such that the idle quality is not impaired to a significant extent. If customer complaints should arise in this respect, attention should be drawn to the fact that this is not an engine malfunction.

2. Catalytic converter heating when idling

The ignition angle (timing) is reduced from 5° crank angle to 0° crank angle on the B25 and B28 in order to prevent the catalytic converter cooling down during longer idle phases. This function does not influence the idle speed quality. The set idle values should be checked with the ignition angle at the reduced (0°) setting.

3. Deleting adaptations on completion of repairs

The adaptations should generally not be deleted on completion of repairs (parts replacement). After replacing the throttle valve (MDK) the adaptation values should be deleted in order to avoid a fault code entry.