The instrument cluster features three bus interfaces which enable the information link (data link/serial) to the connected control units.
These busses are:
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 four 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.
Measures |
Result |
Remarks |
|---|---|---|
Replace instrument cluster (new part) |
The manipulation point is set with the ignition switched on. |
The manipulation point is set since the vehicle identification number in the light switching centre differs from the vehicle identification number in the instrument cluster. |
Re-encode the instrument cluster |
|
Encode the instrument cluster in accordance with the central encoding code |
Encode vehicle identification number into instrument cluster |
|
As long as the vehicle identification number is not coded in the instrument cluster, total odometer recording (only trip odometer recording) does not take place either in the instrument cluster or in the light switching centre (LSZ). |
Switch off ignition and switch on again |
The manipulation point goes out, the instrument cluster adopts the total odometer reading from the LSZ as well as the SIA data. |
The data exchange between the instrument cluster control unit and light switching centre control unit for mutual data storage (SIA data, total odometer reading, vehicle identification number etc.) is now OK. again. |
Measures |
Result |
Remarks |
|---|---|---|
Replace light switching centre (new part) |
The manipulation point is set with the ignition switched on. |
The manipulation point is set since the vehicle identification number in the light switching centre differs from the vehicle identification number in the instrument cluster. |
Re-encode light switching centre |
|
Encode the light switching centre in accordance with the central encoding code |
Encode vehicle identification number in the light switching centre |
|
As long as the vehicle identification number is not coded in the light switching centre, the total odometer reading will not be recorded in the light switching centre. |
Switch off ignition and switch on again |
The manipulation point goes out, the light switching centre adopts the total odometer reading from the instrument cluster as well as the SIA data. |
The data exchange between the instrument cluster control unit and light switching centre control unit for mutual data storage (SIA data, total odometer reading, vehicle identification number etc.) is now OK. again. |
Only replace both control units at the same time when this is unavoidable (stored total odometer reading is irretrievably lost).
Note
Disconnect battery !
Measures |
Result |
Remarks |
|---|---|---|
Replace instrument cluster and light switching centre with battery disconnected (new parts) |
The manipulation point is set with the ignition switched on and the total odometer reading (mileage) is set to zero. |
The previous total odometer reading (mileage) is irretrievably lost. |
Encode instrument cluster and light switching centre |
|
Encode instrument cluster and light switching centre in accordance with the central encoding code |
Encode vehicle identification number in the instrument cluster and in the light switching centre |
|
As long as the vehicle identification number is not coded, the total odometer reading (mileage) is recorded in the instrument cluster and in the light switching centre. |
Switch off ignition and switch on again |
The manipulation point goes out, the LM adopts the total odometer reading (mileage) from the instrument cluster as well as the SIA data. |
The data exchange between the instrument cluster and light switching centre for mutual data storage (SIA data, total odometer reading, vehicle identification number etc.) is now OK. again. |
Note
Although exchanging one of the two control units is possible in principle, it should, however, be avoided wherever possible.
Measures |
Result |
Remarks |
|---|---|---|
As a check, an instrument cluster or light switching centre control unit from another vehicle is installed |
The manipulation point is set with the ignition switched on and the instrument cluster continues to record the total odometer reading. |
For as long as the vehicle identification number differs, the total odometer reading is only recorded in the instrument cluster. There is no total odometer reading calibration with the light switching centre. |
Following functions are displayed or used for a function:
Display/function |
Required signal |
|---|---|
Speed display |
Position signal tw from ASC/DSC control unit |
Engine speed display |
Engine speed information from engine control unit (CAN-bus) |
Fuel consumption (economy) display |
Injection information ti from engine control unit (CAN-bus)/ engine speed information from engine control (CAN-bus)/position signal tw from ASC/DSC control unit |
Fuel gauge |
Resistance value of both lever sensors (analog input) |
Coolant temperature gauge |
Coolant temperature information from engine control unit (CAN-bus) |
Service interval display |
Injection information ti from engine control unit (CAN-bus) |
Reset service interval display |
Line connection to diagnostic socket |
Total odometer reading |
Position signal tw from ASC/DSC control unit |
Trip odometer reading |
Position signal tw from ASC/DSC control unit |
Outside temperature display with ice warning (+3 o C) |
Resistance value from outside temperature sensor/ position signal tw from ASC/DSC control unit |
Text display |
Simple text display for time, total distance recorder, trip recorder, remaining kilometres (miles) to service inspection, on basic BC outside temperature, fuel consumption, range and average speed operable via steering column switch. |
Dimming instruments |
Dimmer signal from light switching centre (LSZ)/ internal signal from photo transistor |
Gong activation |
Gong tone 3 (T3) priority gong at 1 kHz |
Speed-A signal/output |
Speed signal |
Brake pad wear indication |
Resistance value of brake pad wear sensor and sensor lines arranged in a ring (analog positive output to analog ground input). |
Transmission program display (automatic transmission) |
Transmission program information from transmission control unit (CAN-bus) |
K-bus (body bus) |
Information link (data link/serial) to connected control units |
Diagnosis bus |
Information links (data link/serial) to BMW service tester systems |
System test (Test No. 2):This system test facilitates simple visual assessment of the instrument cluster (pointer instruments, displays, lighting, warning lamps and indicator lamps).
Selecting system test function
The system test is started by pressing the left-hand button in the instrument cluster (trip recorder reset button. The button must be pressed and held with the ignition lock in "0" position, now turn the ignition lock to position "1" (terminal R radio setting) and release the button. When "tESt 1." appears in the display press the button once again, "tESt 2." now appears. After a short period of time, the display changes to "tESt 2.0". The system test can now be started by pressing the button once again.
By switching the terminals, ignition lock from position "1" (terminal R radio setting) to position "2", the two-coloured indicator lamps are activated yellow and red. On completion of the system test, it can be repeated by pressing the button once more.
These elements are:
Indicator and warning lamps for:
All test functions, apart from test numbers one and two, are interlocked and must be released by means of test function number nineteen.
Selecting test functions
The test functions are started by pressing the left-hand button in the instrument cluster (trip recorder reset button. The button must be pressed and held with the ignition lock in "0" position, now turn the ignition lock to position "1" (terminal R radio setting) and release the button. Once " tESt 1. " appears in the display the required test can be selected by pressing the button. " tESt 2. " " tESt 3. " " tESt 4. " etc. now appear in the display. After a short time, the display changes to " tESt x.0 " (x stands for selected test group), by pressing the button once again, it is possible to switch to another test in the test group or, as in the system test, start the respective test.
If the test is a locked test (test 3 to 21) the lock is released with test 19 by pressing the trip recorder button when "_L_oFF" appears in the display. The display then jumps to test 0 so that the corresponding test group can be selected by briefly pressing the button.
Test No. |
Function |
|---|---|
1 |
Instrument cluster identification |
|
1.0 Vehicle identification number without ASCII characters |
|
1.1 Constant for road speed calculation (K-number) |
|
1.2 BMW part number |
|
1.3 Coding index, diagnosis index and bus index |
|
1.4 Date of manufacture of instrument cluster (week/year) |
|
1.5 Hardware number, software number |
|
1.6 Not used |
|
1.7 CAN-bus index, revision index |
2 |
System test |
3 |
Service interval indicator - data (SIA-data) |
|
3.0 SIA-data, litres since last reset |
|
3.1 SIA-data, time inspection, time counter since last reset |
4 |
4.0 Momentary consumption values in l/100 km |
|
4.1 Momentary consumption values in l/h |
5 |
5.0 Range-consumption (calculation value for range) |
|
5.1 Momentary range |
6 |
6.0 Fuel tank values of left/right lever-type sensors (display LLLRRR corresponds to LL,L and RR,R in litres. L corresponds to litre value left, R corresponds to litre value right) |
|
6.1 Fuel tank values of both lever-type sensors averaged (display __SSSS corresponds to SSS,S sum of both sensor values in litres) |
|
6.2 Internal fuel tank calculation values |
7 |
7.0 Coolant temperature in degrees Celsius (as from ignition lock position 2, terminal 15 "ON") |
|
7.1 Outside temperature in degrees Celsius with 0.5 degrees resolution |
|
7.2 Momentary engine speed in revolutions per minute |
|
7.3 Momentary road speed in kilometres per hour |
8 |
Values from analog/digital converter (ADC, internal calculation values) |
9 |
System voltage terminal 30 in Volt |
10 |
not used |
11 |
not used |
12 |
not used |
13 |
Triggering of acoustic signals (gong T3) |
14 |
not used |
15 |
not used |
16 |
not used |
17 |
not used |
18 |
not used |
19 |
Locking and Unlocking Test Functions |
20 |
not used |
21 |
Reset instrument cluster (software reset) |
0 |
End of test, the test mode can be exited with this function. |