Mercedes S-Class W-220

since 1998 of release

Repair and car operation

W220 Mercedes
+ Mercedes-Benz Cars of a class S (W220)
+ Operation manual
+ Routine maintenance
+ Engine
+ cooling and heating Systems
+ Power supply system and release
- Engine electric equipment
   - Ignition and engine management system
      Basic elements of system of microprocessor management
      Checks of a control system by ignition and injection
      Search of malfunctions - the general information and preliminary checks
      Check and adjustment of a corner of an advancing of ignition
      Spark plugs
      Self-diagnostics of systems of electronic control of the second generation of OBD II
      The controler of interface of the personal computer with onboard system of self-diagnostics of OBD II according to protocols of the SAE standards (PWM and VPW) and ISO 9141-2
      Oscillograph application for supervision of signals in chains of control systems
      Digital tire of data of CAN
   + charge and start Systems
+ Automatic transmission
+ Power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ electric equipment Cхемы


Self-diagnostics of systems of electronic control of the second generation of OBD II

Multimeter connection to control unit sockets the engine by means of an auxiliary splitter

001 — ECM Sockets
003 — the Digital multimeter
050 — a 126-contact splitter
108 — the Verifying cable
N3/10 — the Control unit of the engine (ME-SFI)

A-F — Sockets
II1/63 — splitter Sockets
III63/126 — splitter Sockets
At a rassoyedineniye of sockets on ECM the central socket (D) is established to the last.
Important: The socket with red marking is not required now as in ECM is not provided the corresponding function.

The structure of OBD system includes some diagnostic devices making monitoring of separate parameters of systems of decrease in toxicity and fixing revealed refusals in memory of the onboard processor in the form of individual codes of malfunctions. The system makes also check of sensors and actuation mechanisms, supervises vehicle service cycles, provides storing possibility even failures quickly arising in the course of work and cleaning of the block of memory.

All models described in the real Management are equipped with system of onboard diagnostics (OBD II). A basic element of system is the onboard processor more often called by the electronic module of management (ESM), or the module of management of functioning of the power unit (RSM). RSM is a brain of a control system of the engine. Basic data arrive on the module from various information sensors and others electronic a component (switches, the relay etc.) . On the basis of the analysis of data arriving from information sensors, and according to put in memory of the processor in base parameters, RSM develops commands for operation of various operating relays and actuation mechanisms, carrying out thereby adjustment of working parameters of the engine, and providing maximum efficiency of its return at the minimum fuel consumption. Data read-out of memory of the OBD-II processor is made by means of the special scanner connected to the 16-contact diagnostic socket of reading of a database (DLC), located in car salon.

In principle, reading written down in memory of system of self-diagnostics of codes of malfunctions probably, on some models, by means of a lamp «Check the engine» or by means of an auxiliary light-emitting diode, and also on the codes highlighted on the display automatic Quarter.

Data on diagnostic devices

Check of serviceability of functioning a component of systems of injection and decrease in toxicity of the fulfilled gases is made by means of a universal digital measuring instrument (multimeter). Use of a digital measuring instrument preferably for several reasons. First, on analog devices it is rather difficult (sometimes, it is impossible), to define result of the indication to within the 100-th and thousand shares while at inspection of the contours including in the structure electronic components, such accuracy takes on special significance. The second, the reason that fact is not less important that the internal contour of a digital multimeter, has rather high impedance (internal resistance of the device makes 10 megohms). As the voltmeter is connected to a checked chain in parallel, accuracy of measurement by that is higher, than the smaller current will pass through actually device. This factor is not essential at measurement of rather high values of tension (9 ÷ 12 In), however there is defining at diagnostics of elements giving out low-voltage signals, such, as, for example, a l-probe where it is a question of measurement of shares of volt.

Parallel supervision of parameters of signals, resistance and tension in all chains of management is possible by means of a splitter included consistently in the socket of the control unit by the engine. Thus on the switched-off, working engine or during car movement, measurement of parameters of signals on splitter plugs from what the conclusion about possible defects is drawn is made.

Special diagnostic scanners or testers can be applied to diagnostics of electronic systems of the engine, automatic transmission, ABS, SRS and other with a certain cartridge (if it is provided), a universal cable and the socket. Besides, it is possible to apply the expensive specialized automobile diagnostic computer which has been specially developed for complete diagnostics of the majority of systems of modern cars to this purpose (for example, Launch HiTech firm ADC2000). Also, it is possible to apply scanners and specialized diagnostic analyzers to this purpose, for example FDS 2000, Bosch FSA 560 (, KTS 500 (0 684 400 500) or the ordinary personal computer with the special adapter, a cable (for example, a set 1 687 001 439) and the established program OBD II browser.

Some scanners, besides usual operations of diagnostics, allow, at connection with the personal computer, to unpack being stored in memory of the control unit schematic diagrams of electric equipment (if are put), to program anticreeping system, to observe signals in car chains in real time.

For diagnostics of your car you can download the free version of a browser of OBD II also from our site

Diagnostics of electronic control systems by the engine, injection and ignition, automatic conditioner of air and ABS/ASR/ETS/ESP

Arrangement of the 16-contact diagnostic socket if it is established

The 16-contact diagnostic socket of system of onboard diagnostics of OBD II (on the USA models)

conclusion No.


Signal TNA (gasoline); TD (diesel engine)
Connection with the case, C. 31
The case - an alarm conclusion, C. 31
Tire of data of CAN high level (salon)
Engine (ME) electronics
Food, C. 87
Antiprobuksovochny system (ETS/ESP)
Control unit transmission (ETC)
The activity module (AAM – All Activity Module)
Safety systems
Tire of data of CAN. Low level (salon)
IC control panel
Battery plus through a safety lock. Energized at any position of the lock of ignition, C. 30

The 38-contact diagnostic socket for extraction of blinking codes (if it is established)

Connect wires according to the scheme. The wire shown by the faltering line, is connected to a certain conclusion for diagnostics of a certain system (address to the list of purpose of contacts):

  • to a conclusion 4 for diagnostics of system of injection;
  • to a conclusion 8 for diagnostics of the main unit;
  • to a conclusion 17 for diagnostics of system of ignition;
  • to a conclusion 19 for check of the block of diagnostics.
Purpose of contacts of the 38-contact diagnostic socket


Weight, contour 31 (W12, W15, electronic grounding)


Tension, contour 87


Tension, contour 30


System of electronic injection (diesel engines)

Fuel injection with electronic distribution (diesel engines)

Consecutive electronic injection of fuel (diesel models)

System consecutive distributed injections/ignitions HFM (engines 104)

System of the consecutive distributed injection of LH (engines 104, 119, 120 [the rights.])

System of the consecutive distributed injection of ME (engines 119, 120 [the rights.])


System of the consecutive distributed injection of LH (engines 120 [a lion.])

System of the consecutive distributed injection of ME (engines 120 [a lion.])


System of anti-blocking of brakes

Electronic antiprobuksovochny system

Pro-slipping adjustment at acceleration

Program of electronic stabilization


Electronic acceleration

Control system of speed/stabilization of turns of idling.


Base module.

Amplifier of emergency braking.


Automatic blocking of differential.


Electronic control by transmission.


Adaptive system of amortization.


Sensitive to speed of the car system of hydrostrengthening of a wheel.


TNA signal (petrol models), LH-SFI engines.

TN signal (petrol models), HFM (ME) engines - SFI.


Signal, information on porosity, engines 119, 120 LH-SFI (rights.).


Signal, information on porosity, engines of 120 LH-SFI (lion.).


Combination of devices.


Air central air.


Ignition system with the distributor, engines 104, 119 and 120 (the rights.)

TD signal (temporary division) (diesel models)

TN signal, LH-SFI engines.


Ignition system with the distributor, LH-SFI engines.


Diagnostic module.


Pneumatic equipment.




Anticreeping alarm system.


Are not used.


System Parktronik.


It is not used.


Safety pillows / натяжители ETR (SRS) belts


Remote control by the uniform lock.


Are not used.


Communication system and navigation.


It is not used

Reading and removal of blinking codes

Reading of codes is made by means of the simple scheme from the push-button switch and a light-emitting diode. Depending on type of the diagnostic socket and the system subjected to diagnostics, connection is made according to presented on illustrations.


1. Connect the scheme according to an illustration.
2. Include ignition.
3. Press and hold the switch button during 2-4 seconds and release it. In 2 seconds the light-emitting diode will give out a code which value is equal to number of flashes. Duration of flash of 0.5 seconds, interval of 1 second. Identify a code by interpretation. For reading of the following code again press the button. For deleting of this code press the button and hold it during 6-8 seconds Besides, on some models, deleting of codes in memory is possible at shutdown of the negative plug of the storage battery.
4. Switch off ignition and disconnect the scheme for check.

Diagnostics of electronic system of the automatic conditioner of air (KV)

Diagnostic codes besides the special scanner can be считаны from the Quarter control unit display. Codes of malfunctions remain even at shutdown of the storage battery.

Reading of codes

Include ignition;
Transfer handles of a choice of temperature to the provisions HI left and LO right;

During 20 seconds after transfer of handles at the same time press and hold during 5 seconds of the REST and EC button;

The light-emitting diode of the RECIRCULATION key will start to blink and on the display there will be OFF;

Press the right AUTO button more than 1 second. If malfunctions in memory are not fixed, in the left part of the display there will be E, and in the right FF. Otherwise in the left part Ebl, and in right - a malfunction code (address to the list of KV codes below) is displayed;

For a conclusion of a code of the following malfunction press the AUTO button;

For deleting of codes after their complete reading press the right and left AUTO buttons more than 2 seconds. In the left part of the display d, in the right FF is displayed;

By pressing of the right AUTO button there is a restoration of the erased codes (compare to the codes which have been written down earlier);

After removal of codes in the left part of the display E, in the right FF is displayed;

Establish the handle of a choice of temperature in normal situation;

Switch off ignition.