Function requirements, general
Circuit 15R ON
The electronic ignition lock control unit (N73) sends the status of circuit 15 over chassis CAN 2 (CAN E2) to the instrument cluster (A1).
Control/warning messages, general
The control/warning messages in the instrument cluster notify the driver of the current statuses of systems installed in the vehicle.
The instrument cluster can issue indicator and warning messages in the following ways:
Visual output:
Multifunction display (A1p13)
Indicator/warning lamps
Acoustic output:
Warning buzzer (A1h1)
Function check of turn signal lights, acoustic (A1h2)
P54.33-2883-79
Shown on model 166.004 |
A1 | Instrument cluster | A1e38 | Standing lights indicator lamp (as of 01.07.2012) | |
A1e1 | Left turn signal indicator light | A1e41 | Electronic Stability Program warning lamp | |
A1e2 | Right turn signal indicator light | A1e51 | Brake system warning lamp | |
A1e3 | High beam indicator lamp | A1e52 | COLLISION PREVENTION ASSIST warning lamp (with CODE 252 (COLLISION PREVENTION ASSIST)) | |
A1e4 | Fuel reserve indicator lamp | A1e54 | Coolant temperature warning lamp | |
A1e9 | Seat belt warning lamp | A1e58 | Engine diagnosis indicator lamp | |
A1e10 | Parking brake indicator lamp | A1e59 | DISTRONIC warning lamp (with CODE 233 (DISTRONIC PLUS)) | |
A1e11 | Parking brake indicator lamp | A1e66 | Tire pressure monitor warning lamp (with CODE 475 (Tire pressure monitor (Premium)), Schrader) | |
A1e15 | Supplemental restraint system indicator lamp | A1e67 | Low beam indicator lamp | |
A1e16 | Preglow indicator lamp (on diesel engine) | A1e75 | Brake force distribution warning lamp | |
A1e17 | Antilock brake system indicator lamp | A1p8 | Speedometer | |
A1e18 | Rear fog lamp indicator lamp | A1p13 | Multifunction display | |
A1e32 | ESP®/ASR OFF warning lamp |
The messages shown on the multifunction display are split up according to their level of urgency into four categories:
Category 1 (messages with highest priority)
Category 1 messages refer to states and situations which impair safety, and they take priority over messages with lower priority. These messages are displayed and automatically archived in the message memory within a maximum of t = 2 s after they occur, and cannot be acknowledged. When they occur, a brief warning is emitted by the buzzer.
Category 2 (messages with medium priority)
Messages in category 2 require the intervention of the driver and appear with a time delay of a maximum of t = 2 s. These messages also include operating feedback. Category 2 messages can be acknowledged. When they occur, a brief warning is emitted by the buzzer.
Category 3 and 4 (messages with low priority)
These messages are menu displays and only serve as information for the driver (e.g. low washer fluid level). No warning chime is emitted.
Messages with low priority are overlaid by messages with high priority. If several messages with the same priority occur, the message currently displayed is overlaid by the new message after the minimum display time has elapsed.
Function sequence for control/warning messages
The instrument cluster informs the driver about the functionality and status of the installed vehicle systems. Safety-relevant system activities and system malfunctions are shown to the driver in the form of control and warning messages.
The following display options are provided for this purpose:
Visual:
Indicator lamps (green, yellow or blue)
Warning lamps (red)
Multifunction display
Acoustic:
Warning buzzer
Turn signal light function check, acoustic
The instrument cluster is connected via interior CAN (CAN B) and chassis CAN 2 to the vehicle electronics.
Requests to issue control and warning messages from control units that are connected to these CANs are read in by the instrument cluster via interior CAN or chassis CAN 2.
The electronic ignition lock control unit sends requests to issue control and warning messages from control units that are connected with one of the following CANs over chassis CAN 2 to the instrument cluster:
Drive train CAN (CAN C)
Chassis CAN 1 (CAN E1)
Diagnostic CAN (CAN D)
Vehicle dynamics CAN (CAN H)
Drive train sensor CAN (CAN I)
The systems and functions listed in the table below can request the output of control and warning messages via the corresponding control unit.
System / Function | Control unit | Connection | Output | ||
Indicator lamp | Display | Acoustic | |||
AdBlue® exhaust treatment (with CODE U42 (BlueTEC (SCR) diesel exhaust treatment))) | AdBlue® control unit (N118/5) | CAN I / CAN E1 / CAN E2 | - | x | - |
ADAPTIVE BRAKE | Electronic Stability Program control unit (N30/4) | CAN E1 / CAN E2 | x | x | - |
Anti-lock braking system (ABS) | Electronic Stability Program control unit (N30/4) | CAN E1 / CAN E2 | Antilock brake system indicator lamp (A1e17) | x | - |
Electronic Stability Program (ESP®) | Electronic Stability Program control unit (N30/4) | CAN E1 / CAN E2 | ESP®/ASR OFF warning lamp (A1e32) (status ESP® ON/OFF) | x | - |
Fail boost | Electronic Stability Program control unit (N30/4) | CAN E1 / CAN E2 | Brake force distribution warning lamp (A1e75) | x | - |
Exterior lights (ABL) | SAM control unit (N10) | CAN B | High beam indicator lamp (A1e3) | x | x |
Headlamp control unit (N71/1) (with CODE 615 (Bi-xenon headlamp unit with integrated curve illumination) or CODE 621 (Intelligent Light System (left-hand traffic)) or CODE 622 (Intelligent Light System (right-hand traffic)) | CAN E2 | - | x | - | |
Turn signal confirmation | SAM control unit (N10) | CAN B | Left turn signal indicator lamp (A1e1) | - | x |
Lights on warning | SAM control unit (N10) | CAN B | - | x | x |
Active Blind Spot Assist (with CODE 237 (Active Blind Spot Assist)) | Video and radar sensor system control unit (N62/2) | CAN E1 / CAN E2 | - | - | x |
Trailer recognition (with CODE 550 (Trailer hitch)) | Trailer recognition control unit (N28/1) | CAN B | - | x | - |
Audio/Navigation/Communication | Radio (A2) (with CODE 523 (MB Audio 20 radio) or CODE 510 (Audio 20 with CD changer)) or COMAND controller unit (A40/3) (with CODE 527 (COMAND APS with single DVD drive (with navigation)) or CODE 512 (COMAND APS with DVD changer) or CODE 528 (COMAND incl. DVD changer)) | CAN B | - | x | - |
Attention assistance system | Electronic Stability Program control unit (N30/4) | CAN E1 / CAN E2 | - | x | x |
Automatic lane recognition (with CODE (476) (Lane Keeping Assist)) | Multifunction camera (A40/11) | CAN E2 | - | x | - |
Automatic transmission control | Intelligent servo module for DIRECT SELECT (A80) or fully integrated transmission control unit (Y3/8n4) | CAN C / CAN E1 / CAN E2 | - | x | - |
Brake fluid level | SAM control unit (N10) | CAN B | Brake system warning lamp (A1e51) | x | - |
Brake wear indicator | SAM control unit (N10) | CAN B | - | x | - |
COLLISION PREVENTION ASSIST (with CODE 252 (COLLISION PREVENTION ASSIST)) | COLLISION PREVENTION ASSIST controller unit (A90) | CAN E1 / CAN E2 | COLLISION PREVENTION ASSIST warning lamp (A1e52) | - | x |
Damping system (with CODE 489 (AIRMATIC (air suspension with level adjustment and adaptive damping system ADS))) | AIRMATIC control unit (N51/3) | CAN E1 | - | x | - |
DISTRONIC (with CODE 233 (DISTRONIC PLUS)) | DISTRONIC electric controller unit (A89) | CAN H / CAN E1 / CAN E2 | DISTRONIC warning lamp (A1e59) | - | x |
Anti-theft alarm system (ATA) (with CODE 551 (Anti-theft alarm system (ATA))) | SAM control unit (N10) | CAN B | - | x | - |
Parking system (with CODE 220 (PARKTRONIC) or CODE 235 (Active Parking Assist)) | Parking system control unit (N62) | CAN E2 | - | x | x |
Electrical power steering | Electrical power steering control unit (N68) | CAN E2 | - | x | x |
Parking brake warning | Electric parking brake control unit (N128) | CAN E1 / CAN E2 | Parking brake indicator lamp (A1e10) | x | - |
Windshield washer system fluid level | SAM control unit (N10) | CAN B | - | x | - |
Speed Limit Assist (with CODE 513 (Speed Limit Assist)) | Multifunction camera (A40/11) | CAN E2 | - | x | - |
Speed warning (with CODE 623 (Gulf States version)) | Instrument cluster (A1) | Internal | - | x | x |
Seat belt reminder warning | Supplemental restraint system control unit (N2/10), | CAN E1 | Seat belt warning lamp (A1e9) | - | x |
KEYLESS-GO (with CODE 889 (Keyless-Go)) | KEYLESS-GO control unit (N69/5) | CAN B | - | x | x |
Coolant level | SAM control unit (N10) | CAN B | - | x | - |
Coolant temperature | CDI control unit (N3/9) or ME-SFI [ME] control unit (N3/10) | CAN E1 / CAN E2 | Coolant temperature warning lamp (A1e54) | x | - |
Memory adjustment (with CODE 275 (Memory package (driver seat, steering column, mirror)) or CODE P64 (Memory package)) | Driver seat control unit (N32/1) or front passenger seat control unit (N32/2) | CAN B | - | - | x |
Engine oil level warning | CDI control unit (N3/9) or ME-SFI [ME] control unit (N3/10) | CAN E1 / CAN E2 | Engine diagnosis indicator lamp (A1e58) | x | - |
Engine management | CDI control unit (N3/9) or ME-SFI [ME] control unit (N3/10) | CAN E1 / CAN E2 | Engine diagnosis indicator lamp (A1e58) | x | - |
Emergency call system (with CODE 359 (TELEAID emergency call system) or CODE 348 (Emergency call/assistance system)) | Emergency call system control unit (N123/4) | CAN-D | - | x | - |
PRE-SAFE® | Left front reversible emergency tensioning retractor motor (A76) or | CAN E1 / CAN E2 | Supplemental restraint system indicator lamp (A1e15) | x | - |
Tire pressure monitor (with CODE (475) (Tire pressure monitor (Premium)), manufactured by Schrader) | Tire pressure monitor control unit (N88) | CAN E2 | Tire pressure monitor warning lamp (A1e66) | x | - |
Tire pressure loss warning (with CODE 477 (Tire pressure loss warning)) | Electronic Stability Program control unit (N30/4) | CAN E1 / CAN E2 | - | x | - |
Stationary heater (with CODE 228 (Stationary heater)) | Stationary heater control unit (A6n1) | CAN B | - | x | - |
Supplemental restraint system | Supplemental restraint system control unit (N2/10) | CAN E1 / CAN E2 | Supplemental restraint system indicator lamp (A1e15) | x | - |
Fuel cap warning (with CODE 494 (USA version)) | CDI control unit (N3/9) or ME-SFI [ME] control unit (N3/10) | CAN E1 / CAN E2 | Fuel reserve warning light (A1e4) | x | - |
Cruise control | Electronic Stability Program control unit (N30/4) | CAN E1 / CAN E2 | Segment ring | x | x |
Blind Spot Assist (with CODE 234 (Blind Spot Assist)) | Intelligent radar sensor for right rear bumper (B29/5) | CAN E1 / CAN E2 | - | - | x |
Doors OPEN warning | SAM control unit (N10) | CAN B | - | x | x |
Preglow indicator (diesel engine) | CDI control unit (N3/9) | CAN E1 / CAN E2 | Preglow indicator lamp (A1e16) | - | - |
Windshield wiper system (rear) | SAM control unit (N10) | CAN B | - | x | - |
Special case of country-dependent seat belt reminder warning
If, immediately prior to starting a journey or during a journey, a seat belt is detected to be not fitted, the instrument cluster issues a country-specific optical and acoustic seat belt reminder warning.
The Supplemental Restraint System control unit (N2/10) sends information about the status on the seat belts for driver and front passenger via chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster. The instrument cluster evaluates this information for issuing a country-specific seat belt reminder warning.
The seat belt reminder message for the front passenger is only issued, if the front passenger seat is recognized as occupied.
The Supplemental Restraint System control unit sends information on the seat occupancy recognition to the instrument cluster over chassis CAN 1, electronic ignition lock control unit and chassis CAN 2.
A rear seat belt reminder warning is only issued when the total number of fitted seat belts in the rear changes during a journey or when the vehicle is at a standstill, without a rear door being opened.
If the total number of fitted seat belts in the rear changes, the instrument cluster actuates the seat belt warning lamp and the warning buzzer.
The rear control unit (N10/8) sends information on the status of the seat belts in the rear over the interior CAN to the instrument cluster.
An issued rear seat belt reminder warning does not exert any influence on triggered restraint equipment, it is only used to notify the driver.
The manner of how the seat belt reminder warning is issued differs in whether the seat belt reminder warning is prescribed by law or not and is incorporated into the assessment through the New Car Assessment Program (NCAP).
NCAP is an assessment program for safety in new vehicles.
Countries with legally prescribed seat belt reminder:
Extended NCAP:
USA, Canada, up to 31.05.2012 Japan and Korea and up to 31.05.2013 Arab States of the Gulf
Countries without seat belt reminder warning prescribed by law:
European New Car Assessment Program (Euro NCAP): Europe, China, Australia, as of 01.06.2012 Japan and Korea and as of 01.06.2013 Arab States of the Gulf
In countries in which the seat belt reminder is prescribed by law (extended NCAP), the seat belt warning lamp is activated for a period of t = 6 2 s. It is irrelevant here whether the driver seat belt is fitted or not. If the driver's seat belt is not being worn, the instrument cluster also issues an acoustic warning over the warning buzzer.
If the driver seat belt is then fitted, the acoustic warning is stopped.
There is no assessment here of whether the front passenger seat belt is fitted or not.
Only after a period of t = 6 s has elapsed, is the status of both seat belts evaluated.
In countries in which the seat belt reminder warning is not prescribed by law, the seat belt warning lamp is only actuated during the indicator lamp test.
Immediately after detecting that the engine is running, the Supplemental Restraint System control unit evaluates the status of the driver and front passenger seat belts.
If a seat belt is defined to not be fitted, the instrument cluster actuates the seat belt warning lamp. If the vehicle then starts to move, additional successive acoustic warning phases are issued upon reaching a speed of v 25 km/h.
Three or four warning phases may be issued in accordance with the seat belt warning. While they are being issued the seat belt warning lamp is actuated by flashing it at a frequency of f = 2 Hz. After all the acoustic warning phases have expired the seat belt warning lamp is permanently actuated.
Acoustic warning phase 1:
If the vehicle drives off, acoustic warning phase 1 starts to run in the background. When a speed of v 25 km/h is reached, a quiet acoustic warning is sounded at an interval of t = 4 s. The acoustic warning phase 1 lasts for a maximum t = 20 s whereupon acoustic warning phase 2 starts.
Acoustic warning phase 2:
After expiry of acoustic warning phase 1 and as from a speed of v 25 km/h, a quiet acoustic warning is sounded for maximum t = 20 s at an interval of t = 2 s. This is then followed by acoustic warning phase 3.
Acoustic warning phase 3:
After expiry of acoustic warning phase 2 and at a speed of v 25 km/h, a quiet acoustic warning is sounded for maximum t = 20 s at an interval of t = 1 s. This is then followed by acoustic warning phase 4.
Acoustic warning phase 4 (Euro-NCAP only):
Following expiry of acoustic warning phase 3 and as of a speed of v 25 km/h, a loud acoustic warning is sounded for maximum t = 93 s at an interval of t = 0.5 s.
Cancellation of seat belt reminder warning:
The last acoustic warning phase is fully completed.
The seat belt was fitted during the active seat belt reminder warning.
When the vehicle is stationary the vehicle door on the actuating side is opened.
Seat belt reminder warning reactivation:
Seat belt release has been detected again.
If the vehicle is at a standstill and the driver or front passenger door is opened and then closed again.
A new ignition cycle is detected from the time the "Engine running" or "Drive train operational" signal is set.
Referenced documents
- gf5430p9996gr Overview of system components, instrument cluster (IC) component description