Mercedes C-Class

W203 since 2000 of release

Repair and operation of the car

Mercedes-Benz
+ Mercedes-Benz cars of class C (W-203)
+ Operation manual
+ Routine maintenance
+ Engine
+ Cooling system and heating
+ Power supply system and release
- Engine electric equipment
   - System of ignition and engine management
      Removal and installation of coils of ignition
      Checks of a control system of 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
   + System of preheat of the diesel engine
   + Diagnostics of systems of electronic control and diagnostic equipment
   + Systems of a charge and start
+ Manual transmission
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment

System of ignition and engine management

Main data and security measures

Ignition coils


4-cylinder petrol engine 1 — the Forward cover of the engine 2 — the Bolt 3 — Prostavka 4 — the Cover of coils of ignition 5 — the Bolt of M6x25, 9 Nanometers 6 — the ignition Coil 7 — the spark plug Plug 8 — the Spark plug	Engine 111: 28 Of Nanometer Engine 271: 25 Of Nanometer 6-cylinder petrol engine 10 — the ignition Coil 11 — the Spark plug, 28 Nanometers 12 — the Bolt, 8 Nanometers 13 — an ignition Cable with the spark plug plug, from the ignition coil to a spark plug

Scheme of an arrangement of components of control systems. C240 and C320 models


1 — the Forward control unit of the choice and registration of a signal (SAM) with a box of relays/safety locks and the relay of system of admixture of secondary air 2 — the fan relay Module 3 — ECM 4 — the SAM Control unit with a box of relays/safety locks and the relay of a starter	5 — the coupling pedal Sensor switch 6 — the DLC Socket 7 — the Sensor of provision of a pedal 8 — the Back SAM control unit with a box of relays/safety locks and the relay of the fuel pump

The system of ignition develops sparks which make firing of the soaked-up fuel-air mix. For this purpose in ignition coils voltage of 12 V will be transformed to tension of 30000 Century.

The electronic system of direct ignition is a part of a control system of the engine and includes spark plugs, and also ignition coils with the built-in plugs of spark plugs. At the 6-cylinder engine of the coil of ignition and plugs of spark plugs are connected by a short cable.

Distribution of current of ignition on candles the block of electronic control operates.

External adjustment of the moment of ignition is not made. If the moment of ignition deviates a preset value, it is necessary to replace the damaged elements.

The system of ignition does not wear out and does not demand service. According to the schedule of maintenance it is required to replace spark plugs only.

The main data on work and sensors of control systems and injection of petrol and diesel engines are stated in the Section Functioning of a Control System and Injection of the Petrol Engine.
Basic elements of electric equipment, arrangement of control units of ignition and injection of fuel, sensors, valves and elements of the drive are presented on accompanying illustrations.

Security measures during the work with system of ignition and injection

For an exception of traumatizing people and/or damage of system of injection and ignition it is necessary to observe the following:

· Do not concern and do not disconnect ignition wires at the working engine or at the included starter.
· Disconnect and attach pipelines of system of injection and a wire of ignition, and also electric wires of devices of measurement only at the switched-off ignition.
· Do not allow to work with electronic system of ignition to people with a warm stimulator.
· It is impossible to close the plug of 1 coils of ignition on weight.
· During the work with turns of start of the engine, for example, when checking pressure of a compression switch off ignition and disunite the socket of the sensor of provision of a bent shaft.
· Do not attach a control lamp to the plug of 1 coils of ignition.