COMAND - Frequently Asked Questions And Operational Concerns (DTB 24/99-2; MB-NET 269)

COMAND - FREQUENTLY ASKED QUESTIONS AND OPERATIONAL CONCERNS

TECHNICAL SERVICE BULLETIN

SUBJECT

DEALER TECHNICAL BULLETIN 24/99

SERVICE INFORMATION

24/99-1 RECALLS AND SERVICE CAMPAIGNS: WHEN REPAIRING ANY VEHICLE, ALWAYS CHECK THE VEHICLE MASTER INQUIRY FOR OPEN CAMPAIGNS

24/99-2 GROUP 82 - MODEL 220, COMAND: The following COMAND topics are provided to address some frequently asked questions and recent operational concerns.

1. Initializing the COMAND Navigation System: In order for the COMAND navigation system to determine current location (after an extended power down or on initial delivery), it must be allowed to acquire a GPS satellite 'fix'. In order to get this initial 'fix', perform the following:
   1. Insert a CD-ROM for the vehicles current geographic area
   2. Park the vehicle outside in a location where the GPS antenna ('shark fin' on rear glass) has an unobstructed view of the sky (e.g. open parking lot not obstructed by trees or other coverings).
   3. Place the navigation system in the 'Location Map' mode by selecting "Info" from the main navigation screen and then selecting "Location Map". Normally on initial delivery the screen will indicate the default Longitude and Latitude of "9 00' 00"E 50 00' 00"N"
   4. Leave the power on until the system locates itself on the map and the correct latitude and longitude are displayed (this will normally take from 15 to 30 minutes depending on weather conditions and time of day). If security is of concern, the key may be removed and the COMAND system turned on using the "PWR" key; in this power on mode the COMAND unit will automatically turn off after 30 minutes and the system should be initialized. The vehicle may be locked during this time.
2. Setting the Clock: The cluster clock is set automatically by the GPS system whenever a navigation CD-ROM is installed and the system has been properly initialized (see item 1 above). In order for the clock to remain accurate and automatically updated, the navigation CD-ROM must remain installed at all times.
3. Magazine Mix Mode for CD Changer: When in CD mode, there exists an option labeled "Magazine Mix". Normally this mode would result in the following playback sequence:
   1. play 3 tracks randomly on the current CD (4 will actually play; current track + 3 random tracks)
   2. randomly select another disc
   3. play 3 random tracks on the new disc
   4. repeat steps b and c continuously (random, no repeat)

We have identified a bug which prevents the proper operation of this mode. The bug is currently being corrected and will be issued as a software update, along with other enhancements in the near future. DO NOT replace the COMAND unit for this problem as a new unit will not correct the problem. As soon as the fix is developed and tested, the field will be advised how to perform the update.

4. Inaccurate ETA in Navigation Mode: When crossing the date boundary (12:00 midnight) the system is not providing the correct ETA information. This has been identified as a software bug and will be corrected in the upcoming software release (refer to point 3 above).
5. Inaccurate Distance Calculation in Navigation Mode: The COMAND navigation system uses wheel speed inputs from the two front wheels to calculate distance traveled. In order to calculate distance accurately, the system must be aware of the tire size currently on the vehicle. While COMAND adjusts for normal tire wear automatically, new tires or a change in tires requires a coarse setting to be input by the user or technician.

In order to input this coarse correction factor, refer to pages 184 and 185 in the COMAND owners manual. After this coarse factor has been input, the system will automatically fine tune the speed pulse correlation factor with the aid of GPS signals.