General
The instrument cluster is made up of the instrument cluster electronics ( IKE ) and a display unit ( AE ). The instrument cluster electronics unit ( IKE ) is plugged on to the display unit.Since 5/97 an instrument cluster has been phased-in which features the plugged-on instrument cluster electronics ( IKE ) integrated in the display unit ( AE ). This instrument cluster can replace older instrument cluster versions.
Bus interfaces, via which the information link (serial data link) to the connected control units is established, are integrated in the IKE .
These busses are:
- I-bus (instrumentation bus)
- K-bus (body bus)
- Diagnosis bus (link to diagnostic socket).
- CAN bus (instrument cluster-integrated version phased-in as from 5/97)
Coded data which determine the scope of functions of the instrument cluster electronics ( IKE ) are stored in a non-volatile data memory (data are retained when supply voltage is disconnected).
The various scope of functions includes, for example, the vehicle model and the country language variant.
At present, eight country variants can be chosen:
- Australia/ Gulf States/ South Africa
- Germany
- United Kingdom
- France
- Italy
- Japan
- Canada
- Spain
- USA
Display and Indicator Instruments:
All display and indicator instruments are housed in the display unit. This unit contains display instruments. indicator lamps and the LCD module. The display unit of the instrument cluster is equipped with different display and indicator instruments depending on the vehicle model.
Replacing Instrument Cluster Electronics (IKE):
The tour cases described in the following show the steps which must be taken under certain circumstances in order to ensure trouble-free replacement of the instrument cluster electronics ( IKE ).
These four cases also apply to the integrated version of the instrument cluster phased-in as from 5/97. In this case, the instrument cluster can only be replaced.
Case 1: The control unit for the instrument cluster electronics (IKE) is defective and the light check module control unit (LCM) is OK.
Case 2: The control unit for the instrument cluster electronics (IKE) is OK. and the light check module control unit (LCM) is defective.
Case 3: The control unit for the instrument cluster electronics (IKE) and the light check module control unit (LCM) must be replaced.
Only replace both control units at the same time when this is unavoidable (stored total odometer reading is irretrievably lost).
NOTE: Disconnect battery I
Case 4: As a check, replace the control unit for the instrument cluster electronics (IKE) or the light check module control unit (LCM).
NOTE: Although exchanging one of the two control units is possible in principle, it should, however, be avoided wherever possible.
Scope of Function:
Following functions are displayed or used for a function:
NOTE:
All warning lamps not listed have no functional connection with the instrument cluster electronics ( IKE ). They are only supplied with positive or negative from the display unit of the instrument cluster.
Test Functions:
The test functions which could be called up in the on-board computer in previous series can now be called up in the instrument cluster.
System test (Test No 2): The system test serves the purpose of testing the display unit together with its elements controlled by the instrument cluster electronics ( IKE ).
These Elements Are:
- All pointer instruments
- All LC displays with a segment test and their background lighting
The Indicator And Warning Lamp For:
- Belt warning
- Fuel reserve
- General brake warning lamp
- Parking brake
- Left turn signal indicator
- Right turn signal indicator
- Front fog light
- Rear fog light
- High beam
Pointer Instruments:
During the system test, operation of the pointer instruments is diagnosed and a corresponding fault code is set in the fault code memory if an electrical fault occurs. In addition, particular care must be taken to observe whether the pointers move smoothly and continuously over their entire indication range during the first test run. During the second run within a system test sequence. the pointer instruments are no longer moved continuously and smoothly over their entire indication range. In this case, the electrical drive data are measured at various indication angles of the pointers.
Selecting Test Functions:
All test functions, apart from test numbers one and two, are interlocked and must be released by means of test function number nineteen.
Procedure: Press and hold the check control button (right-hand button in the instrument cluster) at terminal 15 "ON" until "Test No.: 01" appears in the text display (text field for check control messages). The corresponding test can be selected by repeatedly pressing the button. Then activate the set test by pressing the trip odometer reset button (left-hand button in the instrument cluster). If the test is a locked test (test 3 to 21), "Lock ON" will appear after the trip odometer reset button has been pressed. In this case, the checksum of the digits for the vehicle identification number must be set by repeatedly pressing the trip odometer reset button. The test must now be reselected with the CC button and confirmed with the trip odometer reset button. The tests one and two can be confirmed directly and thus selected with the trip odometer reset button.
To Form Checksum: Read out vehicle identification number with test 1.
Display example: "VIN: XY12345"
Cross sum example: 1+2+3+4+5 = 15
Test No. Function
1. Identification instrument cluster electronics ( IKE )
2. System test
3. SIA data
4. Momentary consumption values in 1/100 km and I/h
5. Range consumption and momentary range
6. Fuel tank content values
7. Coolant temperature and engine speed
8. Momentary speed in km/h
9. System voltage terminal 30 in Volt
10. Read out country-specific code
11. Read out units (AM/PM or mm.dd/dd.mm) etc.
12. Average speed for arrival and momentary arrival
13. Triggering acoustic signals
14. Read out of error bytes (self-diagnosis)
15. Display of I/O port statuses
16. free
17. free
18. free
19. Locking and Unlocking Test Functions
20. Entry of a correction factor for average consumption
21. Reset IKE (software reset)