Part 3 of 3

Additional function requirements for coolant level and coolant temperature warning
^ Circuit 15 On (provided by EIS [EZS] control unit)

Function sequence for coolant level and coolant temperature warning
The coolant level in the expansion reservoir is monitored by the coolant level indicator switch (S41).
The status of the coolant level indicator switch is read in by the front SAM control unit. With an excessively low coolant level, the front SAM control unit transmits a corresponding signal via the interior CAN, central gateway control unit and central CAN to the instrument cluster.
The instrument cluster receives this signal and issues a corresponding message on the multifunction display.

The coolant temperature is recorded by the coolant temperature sensor (B11/4). The CDI control unit or the ME-SFI [ME] control unit reads in the coolant temperature sensor signal and transmits the corresponding temperature value to the chassis CAN. The central gateway control unit passes this on to the instrument cluster via the central CAN.
When a coolant temperature of T > 130 °C is reached, the instrument cluster actuates the coolant temperature warning lamp (A1e54) and issues a corresponding message on the multifunction display.

Additional function requirements for engine oil level warning
^ Circuit 15 On (provided by EIS [EZS] control unit)
^ Circuit 61 Off (no signal provided by CDI control unit or ME-SFI [ME] control unit)

Engine oil level warning function sequence
In order to monitor the engine oil level, the engine oil pan has an oil level check switch (S43) (with engine 156, 272, 273, 642) or an oil sensor (oil level, temperature and quality) (B40) (with engine 275, 629) installed in it.
While the oil level check switch only identifies if the engine oil level is at the minimum or not, the oil sensor monitors the engine oil level, the engine oil temperature and the engine oil quality.
The signals of the oil level check switch or oil sensor are read in by the CDI control unit or by the ME-SFI [ME] control unit and evaluated.
If necessary, the CDI control unit or the ME-SFI [ME] control unit transmits a corresponding signal via the chassis CAN, central gateway control unit and central CAN to the instrument cluster.

The instrument cluster receives the signal and issues one of the following messages on the multifunction display:
- "Engine oil level, stop vehicle, turn engine off" (red)
- "Engine oil, service required" (red) (with engine 275, 629)
- "When refueling, top up with 1 liter of engine oil" (yellow) (with engine 275, 629)
- "Reduce engine oil level" (yellow) (with engine 275, 629)
- "When refueling, check engine oil level" (yellow) (with engine 156, 272, 273, 642)

Additional function requirements, preglow indicator (with diesel engine)
^ Circuit 15 On (provided by EZS control unit)

Function sequence, preglow indicator
Preglowing is controlled by the CDI control unit. For the period in which preglowing is active, the CDI control unit transmits a corresponding signal via the chassis CAN, central gateway control unit and central CAN to the instrument cluster. The instrument cluster receives the signal and actuates the preglow indicator lamp (A1e16) accordingly.

Additional function requirements for brake pad wear indicator warning messages
^ Circuit 15 On (provided by EIS [EZS] control unit)

Function sequence for brake wear indicator warning messages
The reaching of the wear limit for the front axle brake pads is detected by the right front brake pad contact sensor (S10/2) and the reaching of the wear limit for the rear axle brake pads is detected by the right rear brake pad contact sensor (S10/4).

When the wear limit for the front brake pads is reached, the vehicle ground is switched through to the front SAM control unit via the front brake pad contact sensor.
When the wear limit for the rear brake pads is reached, the vehicle ground is switched through to the rear SAM control unit via the rear brake pad contact sensor.
The respective SAM control unit then transmits a corresponding signal via the interior CAN, central gateway control unit and central CAN to the instrument cluster.
The instrument cluster receives this signal, actuates the brake fluid warning lamp and issues a corresponding message on the multifunction display.

Additional function requirements for brake fluid level warning messages
^ Circuit 15 On (provided by EIS [EZS] control unit)

Function sequence for brake fluid level warning messages
if the fluid level in the brake fluid reservoir is too low it is detected by the brake fluid check switch (S11).
The status of the brake fluid check switch is read in by the front SAM control unit. With an excessively low fill level, the front SAM control unit transmits a corresponding signal via the interior CAN, central gateway control unit and central CAN to the instrument cluster.
The instrument cluster receives this signal, actuates the brake fluid warning lamp and issues a corresponding message on the multifunction display.

Additional function requirements for windshield washer system fluid level warning messages
^ Circuit 15 On (provided by EIS [EZS] control unit)

Function sequence for windshield washer system fluid level warning messages
The fluid level in the washer fluid reservoir is monitored by the windshield washer system fluid level indicator switch (S42 The status of the windshield washer system fluid level indicator switch is read in by the front SAM control unit. With an excessively low fill level, the front SAM control unit transmits a corresponding signal via the interior CAN, central gateway control unit and central CAN to the instrument cluster. The instrument cluster receives this signal and issues a corresponding message on the multifunction display.

Turn signal confirmation function sequence
The acoustic feedback about the active turn signal light actuation is implemented by the acoustic turn signal indicator (A1h2) integrated into the instrument cluster. Visual feedback takes place via the left turn signal indicator lamp and right turn signal indicator lamp.

Additional function requirements for engine-control control/ warning messages
^ Circuit 15 On (provided by EIS [EZS] control unit)

Function sequence for engine-control control/warning messages
If there is a fault in the fuel injection system, the ignition system or in the exhaust system, the ME-SFI [ME] control unit sends a corresponding signal via the chassis CAN, central gateway control unit and central CAN to the instrument cluster. The instrument cluster then actuates the engine diagnosis indicator lamp (A1e58).

Additional function requirements for tank cap warning (with code (494) USA version)
^ Circuit 15 On (provided by EIS [EZS] control unit)

Function sequence for tank cap warning
If the rear SAM control unit identifies an open tank cap, it transmits a corresponding signal via the interior CAN, central gateway control unit and central CAN to the instrument cluster.

The instrument cluster receives this signal, flashes the fuel reserve warning lamp (A1e4) and issues a corresponding message on the multifunction display.