General

General:

At series launch. the instrument cluster (basic) features two bus interfaces which enable the information link (data link/serial) to the connected control units.

These busses are:

- K-bus (body bus)

- Diagnosis bus (link to diagnostic socket).

A further bus interface provides the link to the automatic transmission for as long as the instrument cluster does not feature a CAN interface. On manual transmission vehicles, the reverse switch status is read in via this connection.

Coded data which determine the scope of functions of the instrument cluster 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, nine country variants can be chosen:

- Australia/ Gulf States/ South Africa

- Germany

- United Kingdom

- France

- Italy

- Japan

- Canada

- Spain

- USA

Replacing Instrument Cluster:

The four cases described in the following show the steps which must be taken under certain circumstances in order to ensure trouble-tree replacement of the instrument cluster.




Case 1: The instrument cluster control unit is defective and the light check module control module (LCM) is OK.




Case 2: The instrument cluster control unit is OK. and the light check module control module (LCM) is defective.




Case 3: The control unit for the instrument cluster and the control unit for the light check module (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!




Case 4: As a check replace the control unit for the instrument cluster 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

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 which can be controlled from the instrument cluster.

Controlled Elements Are:

- All pointer instruments

- All LC displays with a segment test and their background lighting

Indicator And Warning Lamps For:

- Belt warning

- Fuel reserve

- General brake warning lamp

- Parking brake

- Left and right turn signal indicators

- Front and rear tog light

- High beam

- Gear indicator (automatic transmission)

- Service interval display SIA

- Check control displays (it coded)

- Air suspension

- Fault automatic transmission

- Engine oil level


Pointer Instruments. During the system test sequence, activation of the pointer instruments is diagnosed and the defect code memory is set in the event of an electrical fault occurring. 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.

Selection Of 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: With terminal R "ON", press the trip odometer reset button (left-hand button in the instrument cluster) until "__tESt 1._" appears in the display of the instrument cluster. The corresponding test (system test corresponds to test 2 "__tESt__2._") can be selected by repeatedly pressing/releasing the button within 1 second. The first subfunction of the set test then appears after approx. 1 second. The subfunction (the system test has no further subfunction) of the corresponding test can be selected by further pressing the button. Since test 2 (system test) has no further subfunction, the system test is triggered after the display "__tESt__2.0" appears and the trip odometer reset button is pressed. If the test is a locked test (test 3 to 21) this is confirmed by pressing the trip odometer button when "_L_oFF" appears in the display. The display then jumps to test 0 so that the corresponding test can be selected by briefly pressing the button

Test No. Function:
1. Identification Instrument Cluster
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, outside temperature, current engine speed, current road speed
8. ADC values (system voltage, voltage at left and right lever sensor, voltage at photo transistor and BVA, voltage at coolant and outside temperature sensor)
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. not used
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 instrument cluster (software reset)
0. End of test, the test mode can be exited with this function.