Driver Information - Overview BMW Z4 E85/E86

Model: E85

Production: All

Instrument Cluster

The instrument cluster in the Z4 has a sporty appearance in line with a roadster. The instrument cluster is very compact. The needle instruments are integrated in 2 housing attachments. The two needle instruments for the speedometer and the tachometer are thus the predominant visual features.

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The needle instruments for the fuel gauge and the coolant temperature gauge are integrated in the tachometer. The speedometer incorporates an LC display, which shows e.g. the total mileage (odometer), the trip distance (trip odometer), the time, the on-board computer functions and the SIA service interval indicator.

Between the large needle instruments are the indicator and warning lamps and the program and gear display. The program and gear display is only featured in vehicles with automatic transmissions and SMG sequential manual gearboxes.

The instrument cluster is the central gateway in the bus network.

Scheme 245

Instrument-Cluster Plug Connection

The 26-pin plug connection is located on the reverse side of the instrument cluster.

Scheme 246

New System Features/Modifications

The main feature of the instrument cluster in the Z4 is its new design

1. The indicator and warning lamps between the needle instruments. The coolant temperature gauge and the fuel gauge are integrated in the tachometer.
2. Additional indicator and warning lamps (e.g. Electric Power Steering EPS) are integrated.
3. The automatic gearbox or Sequential Manual Gearbox SMG has a liquid-crystal display for indicating the gear.
4. The instrument cluster of the Z4 has a gateway function between the bus systems (as in the E46) K-Bus, PT-CAN Bus and diagnosis bus.
5. The lighting of the instrument cluster is controlled by means of the K-Bus.
6. The instrument cluster has a modified voltage supply with undervoltage detection.
7. The acoustic alarms and test functions have been expanded.

System Components

The instrument-cluster system comprises the following components

Scheme 247

1. Needle instruments
2. Indicator and warning lamps
3. LC display
4. Program and gear display for automatic gearbox and SMG Sequential Manual Gearbox
5. Acoustic generator for outputting acoustic alarms
6. Acoustic generator for outputting turn-signal flasher rate
7. Two setting buttons, integrated in instrument cluster
8. Connected components which serve to activate the displays/ indications in the instrument cluster.

Display Areas

The instrument cluster is divided into the following display areas

1. Needle instruments
2. Indicator and warning lamps
3. LC display
4. Program and gear display for automatic transmission and Sequential Manual Gearbox (SMG)

Instrument-Cluster Lighting

The speedometer and the tachometer are illuminated by slit light between the dial face and the graduated dial. The brightness of the dial-face, needle and display illumination (dimming) is determined by the LSZ light switch center. The lights ON signal is transmitted from the LSZ light switch center to the instrument cluster (via the K-Bus). The dimming signal is also transmitted via the K-Bus. The LSZ evaluates the following input signals to control dimming

1. Dimmer (knurl in light switch center)
2. Photoelectric cell for ambient brightness (in light switch center)

Because the dimming signal is sent via the K-Bus, there is no need for terminal 58g.

Instrument Cluster Power Supply

The power supply of the instrument cluster is by means of a switching controller. The switching controller compensates for voltage fluctuations of the vehicle electrical system in the range from 9 V to 16 V.

Undervoltage: the vehicle voltage is measured as of terminal 30 every 30 milliseconds. As of a voltage of approx. 7.5 V, undervoltage is detected. Then, no more read and write accesses are permitted to the EEPROM. Prior to a possible undervoltage reset, the instrument cluster initiates a data backup.

Overvoltage: overvoltage is detected in the case of a voltage >16 V. The microcontroller initiates measures to back up the hardware. Data (mileage, SIA data, time, date, etc.) or states are not lost because they are stored in good time. Indicator and warning lamps are switched off or dimmed for the duration of the overvoltage.

Undervoltage Detection

The instrument cluster incorporates an undervoltage-detection facility. Undervoltage detection is performed in the instrument cluster with the aid of a comparator (software-based voltage comparison).

Note. Overvoltage in the electrical system is also detected. In the event of a system voltage >16 volts, it is possible for: Inputs and outputs to be deactivated Indicator and warning lamps to be deactivated or dimmed for the duration of the over voltage

Coolant Temperature Gauge

In the event of coolant over-temperature, a warning sound is issued when the red indicator and warning lamp lights up. The signal is delivered by the DME via the PT-CAN Bus.

Fuel Gauge

The indicator lamp is activated when the fuel reserve drops below a threshold coded at the plant (standard = 8 liters).

Indicator Lamps

There are a total of 24 indicator and warning lamps in the instrument cluster of the new Z4. The following two lamps are new additions to the established lamps

1. Indicator lamp for EPS: The Electric Power Steering system is used in the new Z4 for the first time.
2. Indicator lamp for lamp monitoring: This lamp indicates lamp failure in the headlights, rear lights and brake lights and is activated by the light switch center.

The instrument cluster receives input signals through the following channels

Scheme 248

1. Via the K-Bus
2. Via the PT-CAN Bus
3. Directly from the sensors

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Scheme 250

Scheme 251

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Pre-Drive Check

The Pre-drive Check is a test of important indicator and warning lamps. In the Pre-drive Check, these indicator and warning lamps are activated for 2 seconds with terminal 15 ON.

All the indicator and warning lamps are deactivated at the end of the Pre-drive Check.

LC Display

The LC display is located between the speedometer and the tachometer. With terminal 15 OFF, run-on operation is possible provided the SMG is still transmitting CAN telegrams.

The LC display is integrated in the speedometer. It has been adapted to the E85 instrument cluster and operates in the same way as that of the E46.

Scheme 253

Program And Gear Display

In cars fitted with an automatic gearbox (5HP19) or an SMG Sequential Manual Gearbox, the program and gear display is featured in a separate LC display.

Scheme 254

Acoustic Generators

Depending on the incident, the acoustic alarms are output once or intermittently.

The following acoustic alarms are new

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1. Coolant over-temperature
2. Fuel-reserve threshold

Seat Belt Reminder

The seat-belt reminder for USA is activated with terminal 15 ON if the seat-belt contact is not closed. The acoustic alarm is intermittent and lasts for max. 6 seconds. After this time has elapsed, only the indicator and warning lamp remains lit.

Setting Buttons

The left button (S/R for Set/Reset) is used to reset the trip odometer reading, to call up the test functions and to call up the reset menu for the service interval indicator.

Scheme 256

The right button (clock symbol) is used to set the time and to switch the service interval indicator (remaining distance/service date or vice versa). To set clock, press and hold button #2 until hour flashes, then tap to change hour, press and hold again until minutes appear.

Bus Network

The instrument cluster is the central gateway (interface) for the bus network. The bus systems PT-CAN Bus, K-Bus and diagnosis bus and the byteflight are interconnected in the instrument cluster.

The byteflight is connected via the Safety and Information Module SIM (= gateway) to the K-Bus.

Scheme 257

Instrument Cluster As Gateway

The instrument cluster is the interface between K-Bus, PT-CAN Bus and diagnosis bus. The instrument cluster communicates with other control units in the car via the K-Bus (single-wire) or the PT-CAN Bus (two-wire).

On-Board Computer

The on-board computer functions are the same as those of the E46. A new feature in the E85 is the possibility of combining time and outside temperature in the display depending on the equipment specification.

On-Board Computer Display In Navigation-System On-Board Monitor

In cars equipped with the High navigation system, the on-board computer functions are displayed in the pop-up on-board monitor (Central Information Display CID).

The "Distance to junction" navigation data is displayed in parallel in the instrument cluster.

Settings (e.g. units or reset) which are made at the navigation system controls using the rotary pushbutton are sent by bus telegram to the instrument cluster.

The date can be set at the navigation-system controls. The date is administered in the instrument cluster and shown in the on-board monitor.

Redundant Data Storage (RDA)

The kilometer reading/mileage and the data of the SIA service interval indicator are stored redundantly in the following control units: instrument cluster, LSZ light switch center and EWS electronic immobilizer. The above-mentioned data are thus retained when the control units are replaced.

Test Functions

The test functions are used by service mechanics to check the coding. They also provide help in troubleshooting without the diagnostic tester.

The test functions are only shown in the instrument-cluster LC display.

The test functions are activated by pressing the left setting button in the instrument cluster (S/R, 5 seconds) with terminal R or terminal 15 ON. In addition, the test functions can still be called up by pressing the left setting button (S/R for Set/Reset) in the instrument cluster with simultaneous activation of terminal R.

The test functions are shown in the odometer and trip-odometer display areas in the top line of the display.

The display of the on-board computer function is retained in the bottom display line.

Test Function 19

Only the first two test functions are freely accessible. All further test functions are locked from the third test function. The lock can only be removed by means of test function 19.

In test function 19, the display switches in intervals of 1 second from L_on to L_oFF (Lock on and Lock off). The test functions are unlocked or locked by pressing the left setting button (S/R for Set/Reset).

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Unlocking Test Functions

While L_oFF is displayed press the left setting button (S/R for Set/ Reset) in the instrument cluster. The cluster will be unlocked and all test functions are accessible. The display jumps to test function 0.

Locking Test Functions

While L_on is displayed press the left setting button (S/R for Set/Reset) in the instrument cluster. The cluster will be locked. Only tests #1 and #2 will be available while the cluster is locked.

Note. The test functions are always locked after a terminal has been changed.

Terminating Test Functions

The test functions are terminated by terminal R OFF. With terminal R ON, the test functions are exited by

1. Pressing the left setting button (S/R for Set/Reset) for longer than 5 seconds
2. Calling up the test function 21

Overview Of Test Functions

OVERVIEW OF TEST FUNCTIONS

Visual System Test

In the visual system test, all the indicator lamps and lights - with the exception of the ABS warning lamp - are activated briefly. The needle instruments are moved from the lower to upper stop and back again.

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Diagnosis

Component replacement and trial replacement There are three possible combinations for replacing the instrument cluster/light switch center

1. Instrument cluster faulty, light switch center OK
2. Light switch center faulty, instrument cluster OK
3. Light switch center and instrument cluster must be replaced

Simultaneous replacement of the light switch center and the instrument cluster must be avoided. The odometer reading will be lost. In principle it is also possible to carry out a trial replacement of the instrument cluster/light switch center.

Car & Key Memory

There are different car-memory functions for the E85 with regard to the display of units in the instrument cluster.

CAR MEMORY SPECIFICATION

SIA IV Service Interval Indicator

The present SIA IV is the service interval indicator to be found in the current E46.

Scheme 260