Automatic Climate Control (ACC) Service Menus

There are three hidden menus available in the W220 Auto Climate Control (ACC). These are used to:

• Access/Review/Read Auto Climate Control (ACC) Actual Parameter Values,
• ACC Flap/Vent, Engine Fan and A/C Compressor Test, and
• access/review/read and clear/reset Fault/Error Diagnostic Trouble Codes (DTC).

Be warned that accessing these hidden menus requires some technical experience.

Refer to W220 Automatic Climate Control Service Menu Version 4.pdf posted 2014-06-29 on BenzWorld. http://www.benzworld.org/forums/w220-s-class/1632652-w220-s-class-automatic-climate-control.html

Summary of what the hidden menus can do.

• Access/Review/Read Auto Climate Control (ACC) Actual Parameter Values,

  This Menu allows an access/review/read of the Auto Climate Control (ACC) actual parameter values during normal operation.
  For example the actual temperature sensed by various sensors can be reviewed and the amount of opening of various flaps 
   as determined by the Auto Climate Control (ACC) Module can be monitored.
  Some controls may be varied in real time and the result monitored via this Menu, eg moving the Centre Vent (N18/4) Centre 
   Potentiometer results in Parameter NR.28: changing value from 0% – 100%.

• ACC Flap/Vent, Engine Fan and A/C Compressor Test, and

  This menu allows testing of the Auto Climate Control (ACC) Flaps/Vents/Outlets and the operation of the Engine Coolant Fan 
   and the A/C Compressor.
  For example, each electrically operated Flap/Vent/Outlet can be exercised through its full range of operation whilst 
   subjectively or objectively monitoring the resulting effect on the Auto Climate Control (ACC) air flow and/or output temperature.
  Test Parameter NR.12: allows the Engine Coolant Electric Suction Fan (M4/3) to be tested through most of its operational range; 
   Off, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, On.  Note the engine must be running for this test and hence the fan may not 
   be set to ‘Off’.
  Similarly, Test Parameter NR.13: allows the A/C Compressor to be tested by varying its Capacity from; 
   Off, 1%, 2%, 3% up to 98%, 99%, On.

• access/review/read and clear/reset Fault/Error Diagnostic Trouble Codes (DTC).

  To access/review/read the Automatic Climate Control (ACC) Fault/Error Diagnostic Trouble Codes (DTC) which are permanently stored 
   in the ACC system, and to clear/reset/erase them from ACC memory.
  For example using the clear/reset/erase procedure you can unlock the Air Conditioner (A/C) compressor after recharging if you’ve 
   run out of refrigerant gas.

Be warned that accessing these hidden menus requires some technical experience.