Mercedes S-Class W-140

In 1991-1999 editions

Repair and enterprise of the car

Mercedes S-Class
+ Mercedes Benz cars of the class S (W-140)
+ operation manual
+ Routine maintenance
+ motor
+ cooling systems, heating
+ Systems of power supply and edition
- Electric equipment of the motor
   - Systems of ignition and management of the motor - the general information
      Checks of tax system ignition and injections
      Search of defects - the general information and preliminary checks
      Check and regulation of a corner of Zuvorkommens of ignition
      Spark plugs
      Self-diagnostics of control systems of the pipe OBD
      Diagnostics of electronic system of the automatic conditioner of air (kilowatt)
      Application of an oscillograph for observation of signals of tax system
      Ignition coils - a device detail
      Removal, device and regulation of a sensor of provision of a wave of curve (CMP)
      The distributor of ignition (M119.97 motors) - a device detail
   + systems of freight and start
+ gear shifting boxes
+ Awtomatitscheckaja transmission
+ connection
+ brake system
+ Aufhängung and management
+ body
+ electric onboard equipment

Self-diagnostics of control systems of the pipe OBD

A little diagnostic devices which fix generating monitoring of the separated characteristics of systems of immersion of toxicity and open refusals in memory of the onboard processor in the form of individual Kodes of defects belong to structure of the OBD system. The system makes also check of sensors and actuation mechanisms, controls transport service cycles, guarantees a possibility of Behaltens even of the violations which are quickly arising during work and cleaning of the block of memory.

All models described in the modern management are equipped with system of onboard diagnostics (OBD).

Basic element of system is the onboard processor which is called more often the electronic module of management (JESM), or to the module of management of functioning of the power plant (RSM)

ECM / RSM Life brain of tax system motor. Basic data affect the module about various information sensors and other electronic components (switches, the relay, etc.). On the basis of the analysis of the data acting about information sensors, it is also appropriately necessary in the processor memory in the main characteristics, ECM / RSM correction of performance data of the motor carrying out makes commands for wear of various operating relays and actuation mechanisms thereof, and maximum efficiency of its compensation at the minimum costs of fuel guaranteeing.

Data read-out of the processor memory of OBD is made by means of the special scanner which joins the diagnostic plug of reading of a databank (DLC) or by means of an auxiliary light-emitting diode, and also after Kodes which are lit on the display of automatic kilowatts.

Instructions over diagnostic devices

Check of serviceability of functioning of components of systems of an injection and immersion of toxicity of the working gases is made by means of the universal digital measuring device (multimeter)

Accession of a multimeter to motor control unit plugs by means of auxiliary raswetwitelja

Use of the digital measuring device prefers for several reasons. First, it is difficult after similar devices (enough sometimes, it cannot) be defined result of the statement to within the 100-th and thousand parts while when rechecking contours which admit electronic components to structure such accuracy wins special value. The second, not less important, the reason the fact that an internal contour of a digital multimeter at which is rather high импенданц (internal resistance of the device forms 10 mom). As the voltmeter turns on to the tested chain in parallel, the accuracy of measurement by that becomes higher, than smaller current go by means of actually device. This factor is essential at measurement concerning high values of effort not (9 ÷ 12), defining at diagnostics of the elements which are giving out over signals of low voltage, such as, nevertheless, for example, the probe of l will be where it is about measurement of participations of volt.

Parallel observation of characteristics of signals, resistance and efforts in all chains of management by means of raswetwitelja, the motor control unit which is consistently made in the plug perhaps. At the same time will be on the excluded, working motor or during the movement of the car which performs measurement of characteristics of signals on raswetwitelja clips from what about possible defects consists.

For diagnostics of electronic systems of the motor, automatic transmission, the antiblocking device, SRS and for the rest special diagnostic scanners or testery with a certain cartridge can be used (if it is provided), to a universal cable and the plug. Besides, it is possible to use for this purpose expensive allocated diagnostic autocomputer which is developed for full diagnostics of the majority of systems of modern cars specially (for example, ADC2000 of the Launch HiTech company). Also, for this purpose it is possible to use scanners and the allocated diagnostic analyzers, for example, of FDS 2000, the equipment of firm Bosch of FSA 560 (www.bosch.de), KTS500 (0 684 400 500) or the ordinary personal computer with the special adapter, a cable (for example, the offer 1 687 001 439) and a certain brouserom OBD II program.

brousera OBD II for diagnostics of your car you can also unload the free version of the web page of authors of the modern guide arus.spb.ru.

Several scanners, except usual operations of diagnostics, leave, at association by means of the personal computer to, to print basic the control unit in memory to the kept schemes of the electric equipment (if are put) to program protiwougonnuju system to observe signals in car chains in real time.

It is necessary to carry out several inspections on various diagnostic plugs. First of all you make check of porosity of an impulse.

Diagnostics of electronic tax systems motor, injections and ignitions, automatic conditioner of air and ABS/ASR/ETS/ESP

Scheme of an arrangement and design of diagnostic plugs

Arrangement of diagnostic plugs


2 — contact plugs 38 if it is defined 3 — the place of the plug 4 — contact plugs 9 if it is defined

The contact plug 9 for diagnostics of tax system after value of porosity of an impulse, by means of the device for measurement of s.g. the term of the closed condition of contacts of the breaker (dwell meter)


1 — the conclusion of the TD switchboard 2 — a body 3 — the conclusion of diagnostics 4 — the conclusion 1 coil of ignition	5 — the conclusion of 15 coils of ignition 6 — the conclusion +30 7 and 9 — the conclusions to WMT sensor 8 — the screen

Definition of contacts of the diagnostic contact plug 38

The diagnostic contact plug 38 for extraction of the blinking Kodes

Attach lines according to the scheme. The line which is shown by the stopped line joins a certain conclusion for diagnostics of a certain system (address the list of definition of contacts):

To the conclusion 4 — for diagnostics of system of an injection;
To the conclusion 8 — for diagnostics of the central processing unit;
To the conclusion 17 — for diagnostics of system of ignition;
To the conclusion 19 — for check of the block of diagnostics.

Clips of the plug have the following definition:

conclusion No.		Definition
1		Weight, contour 31 (W12, W15, grounding of electronics)
2		Effort, contour 87
3		Effort, contour 30
4	EDA	System of an electronic injection (diesel engines)
	DFI	Fuel injection at electronic distribution (diesel engines)
	IFI	Consecutive electronic injection of fuel (diesel models)
	HFM-SFI	System consecutive distributed injections / ignitions HFM (motors 104)
	LH-SFI	System of the consecutive distributed LH injection (motors 104, 119, 120 [the rights.])
	ME-SFI	System of the consecutive distributed ME injection (motors 119, 120 [the rights.])
5	LH-SFI	System of the consecutive distributed LH injection (motors 120 [a lion.])
	ME-SFI	System of the consecutive distributed ME injection (motors 120 [a lion.])
6	ANTIBLOCKING DEVICE	System of anti-blocking of brakes
	ETS	In an electronic way of antiprobuksowotschnaja system
	ASR	Regulation of probuksowki at acceleration
	ESP	Program of electronic stabilization
7	JEA	Electronic acceleration
	CC/ISC	Tax system speed / stabilization of changes of idling
8	WORLD CUP	Main module
	BAS	Brake assistant
9	ASD	Automatic differential obstacle
10	JET PLANES	Management of a pipe of transmission (AT 722.6)
11	ADS	Adaptive system of depreciation
12	UNION OF RIGHT FORCES	It is susceptible against car speed system of hydro-strengthening of a steering wheel
13		TNA signal (petrol models), LH-SFI motors
		TN signal (petrol models), HFM (ME) motors - SFI
14		Signal, information on porosity, motors 119, 120 LH-SFI (right).
15		Signal, information on porosity, motors 120 LH-SFI (lion).
	INTERNETS	Combination of devices
16	A/C	Air conditioning system
17	W.	System of ignition with the switch, motors 104, 119 and 120 (rights).
		TD signal (wremennuje division) (diesel models)
		TN signal, LH-SFI motors
18	W.	System of ignition with the switch, LH-SFI motors
19	DM	Diagnostic module
20	PSE	Pneumatic equipment
21	CF.	Comfort
23	ATA	protiwougonnaja Signalisierung
24-27		Are not used
28	PTS	Parktronic system
29		It is not used
30	AW	Pillows of reliability / natjaschiteli of ETR (SRS) belts
31	RCL	Remote control of the unified lock
32-33		Are not used
34	CNS	Communication system and navigation
35-38		It is not used

Arrangement of the diagnostic contact plug 16 (on models of the USA)

Identification of clips of the diagnostic contact plug 16 of system of onboard diagnostics (on models of the USA)

Clips of the plug have the following definition:

conclusion No.	Definition
1	—
2	—
3	TNA signal
4	Association by a body, clip 31
5	Body - the alarm conclusion, a clip 31
6	Tire of data of CAN high level
7	Electronics of the motor (ME)
8	Food, kiloliter 87
9	antiprobuksowotschnaja system (ETS)
10	—
11	Transmission control unit (etc.)
12	The activity module (AAM - all Activity modules)
13	Systems of reliability
14	Tire of data of CAN Low level
15	Internets control panel
16	Plus batteries protection device. At effort at any position of the lock of ignition, kiloliter 30

Measurement of porosity of an impulse

EXECUTION ORDER

1. First, take measurement of porosity of impulses which characterize work of tax system quality of mix and to its defects, 4 motor, repeated at the last start. For this purpose demand the device for measurement of s.g. the term of the closed condition of contacts of the breaker (dwell meter), testers of the probe ljambda or a digital multimeter.
2. Attach + the conclusion of the device to 3 contacts of the contact plug 9 and it is negative to a car body.
3. Start and heat the motor up to working temperature.
4. Stop the motor and again will include ignition. Accept the statement of the device at %, and compare to deciphering, below. After start of the motor of the statement of the device have to change, otherwise there is a defect.

Reading and removal of the blinking Kodes

EXECUTION ORDER

1. Reading of Kodes is made by means of the simple scheme from the switch of keys and a light-emitting diode. Depending on type of the diagnostic plug and system which will rely diagnostics you attach the scheme according to an illustration.

2. Will include ignition.
3. Press and hold the switch button within 2-4 seconds (or 5-6 seconds on models from ECM-8 of the EQUIPMENT of BOSh / 93) and dismiss them. The 2nd light-emitting diode whipped will give a code which value equals quantities of the beginning. You identify starting date of 0.5 seconds, an interval 1 second a code after deciphering, below. For reading of the following of Kodes you press the button again. For removal you press this Kodes the button and you hold them within 6-8 seconds (or 8-9 seconds on models from ECM-8 of the EQUIPMENT of BOSh / 93). Besides, on several models, removal of Kodes in memory at shutdown of a negative clip of the battery is possible.
4. Will leave ignition and switch off you the scheme for check.

The controller of connection of the personal computer with onboard system of self-diagnostics of THIS OBD II according to protocols of standards (PWM and VPW) and ISO 9141-2

The controller is not intended accessions to onboard systems of self-diagnostics of the first generation (OBD I)!

Models of production of the enterprise GM, PWM - Ford, to ISO 9141-2 - Asian and European models meet the VPW standard.

General data

Scheme of the organization of the controller of connection with onboard system of self-diagnostics of OBD II

The considered establishment represents the microcontroller which is filled after KMOP (CMOS) technologies. Establishment embodies a type of the elementary scanner and it for reading of diagnostic Kodes and data of the OBD II system (change of the motor, temperature of the cooled liquid and the absorbed air operating with nagrusotschnyje of the characteristic, costs in the air motor, etc.) within the J1979 SOW standard the tire of any execution (PWM, VPW and ISO 9141-2) is intended.

Main destination

For accession to the computer it is enough 3-schilnogo the line, accession to the diagnostic plug is carried out 6-schilnym from the line. Working tension is served as the diagnostic contact plug 16 OBD on the adapter.

Recommendations after the appendix

For accession of establishment to the car not covered cable, lengths cannot be used more than 1.2 m what has a special value at the appendix of the PWM protocol. At the appendix of a cable length bolschej Resistoren resistance on an entrance of establishment (R8 and R9 or R15) follows to reduce. At the appendix of the covered cable, the screen needs to be switched off it is necessary for the purpose of immersion of power.

The cable for accession to the consecutive harbor of the computer can also be not covered. Institution works with length cable to 9 m At significantly bolschej of length of a cable it is steadily necessary to use kommunikator RS 232 is necessary stronger.

Topology of the electric associations proiswolna. At the increased humidity you in addition use schuntirujuschtschije condensers.

The free software (brouser) for reading of Kodes and data can from web pages of producers, or web pages of our publishing house arus.spb.ru is unloaded and it is intended for use under DOS. The insignificant volume of the program device in option "under DOS" allows to contain it on a chest diskette DOS and, to use even on computers which are equipped incompatible DOS with the software. The unwarranted condition is even existence in the computer of the hard drive.

Basic principles of data exchange

If it especially does not remain disgustingly, all numbers in 16-ritschnom a format (conjure) it is given.

Data exchange goes after consecutive Dreidrahtvereinigung without the inizialisazionnogo application of exchange of office messages (handshaking). Establishment listens to channel on existence of messages, outputs the received commands and transfers results to the personal computer (PC) then at once comes back to poll mode. In detail in the controller and data coming from it are organized in the form of a chain of the bytes which are consistently going in turn which is the first to their examinations.

Usually control byte represents number 0 to 15 dec (in decimal calculation) (or 0-F conjure), the descriptive quantity of the following are farther than information bytes. Thus the team will look, for example, 3-bajtnaja the next way: 03 (control byte), 1st byte, 2nd byte, 3rd byte.

The similar format will be as for detailed teams on poll of onboard system of self-diagnostics, and uses for the happening messages which contain the requested information.

It is necessary to notice it is necessary that in control byte only 4 more young people of bit are used, - older bits are withheld among several special teams and personal computers at Initialization of association with the controller can be used and the agreement of the protocol of data transmission, and also to the controller for control of errors of transfer. In particular, the device of older considerable bit (MSB) of control byte makes in case of a mistake by transfer, the controller in unit. By successful transfer of all 4 older bits are established in zero.

There are separated exceptions of the rule of use of control byte.

Initialization of the controller and onboard system of self-diagnostics

For the beginning of data exchange of the personal computer the association device with the controller has to make then to initialize OBD II, the controller and the channel of data.

Association device

After connection of the controller to the personal computer and the diagnostic plug OBD there has to be Initialization for the purpose of prevention of "hanging", which are connected with noise in consecutive lines if its accession to be made it was made to the appendix of power supply of the controller. At the same time elementary check of activity of the interface is made. First of all there will be Einbytesignal 20 conjure, apprehended by the controller as the command for the device of association was able. In reply the controller instead of control only byte sends And ON the FOLLOWING PAGES conjure (255 dec) with and passes into a waiting mode of adoption of data. Now the personal computer can pass to Initialization of the channel of data.

This case one of the few if the controller does not use control byte.

Initialization

In this stage Initialization of the protocol on which data exchange will be made, and in case of the ISO protocol – Initialization of onboard system is made. Data exchange is made under 3 protocols: VPW (General Motors), PWM (Ford) and ISO 9141-02 (Asian / European producers).

There is a mass of exceptions: thus the Mazda "fordowski" the PWM protocol can be used, for example, at poll of several models of cars. Thus it is necessary to try it is necessary to use first of all at emergence of problems of transfer some other protocol.

The choice of the protocol will be from transfer a combination which conjures from control byte 41 exists also the following it is made directly behind it byte which defines protocol type: 0 = VPW, 1 = PWM, 2 = ISO 9141. Thus will be, for example, on team 41 02 conjure Initialization of the ISO 9141 protocol is made.

In reply the controller sends control byte and byte of the status. The MSB device of control byte speaks about existence of problems, at the same time the byte of the status following it will contain the relevant information. At successful Initialization there will be a control byte 01 conjure, it is characteristic on it sent that follows werifikazionnyj of bytes of the status further. In case of the VPW and PWM werifikazionnyj protocols of bytes represents a simple echo of the byte defining over the protocol (0 or 1, as appropriate), at Initialization of the ISO protocol it will be in 9141 digital keys which returned by the onboard OBD processor and are defined what 2 slightly more different about each other versions of the protocol it is used.

The digital key has purely information definition. It is necessary to notice it is necessary that VPW and PWM happens significantly quicker to Initialization of protocols as only transfer of the relevant information to the controller demands.

On models which meet ISO Initialization receives about 5 seconds which are spent for information exchange of the adapter with the onboard processor made with a speed of 5 bod.

It is necessary to pay attention it is necessary the reader that on several models of cars of a family of ISO 9141 Initialization of the protocol stops if the request for the edition of data during a 5-every second interval is not transferred, - it is said means that the personal computer has to make the automatic edition of inquiries each several seconds, even in not aggravated mode.

After the device of association and Initializationes of the protocol budget data exchange which exist from acting from the personal computer of inquiries and answers exposed by the adapter begins.

Data exchange order

Functioning of the controller at the appendix of protocols of a family of ISO in 9141-2 and SEY (VPW and PWM) happens after several various Drehbuchern.

Exchange of THIS according to protocols (VPW and PWM)

At data exchange according to these protocols depreciation happens only to the expert of data that need of a specification subordinated a skhvatyvaniye or return of the expert means. (Seldom) cases the onboard processor can transfer packages which exist more than from the expert in some. In such situation the inquiry has to repeat until all experts of a package are not received.

The inquiry always develops the next way: [control byte], [request for the SOW standard], [number of the expert]. As is even higher, the control byte represents number usually which equals to the full number of the following bytes behind it. Inquiry according to the SOW specifications J1950 and J1979 will be open and there are from heading (3 Bt), sequences of information bytes and byte of control of a mistake (CRC). We will notice that during themselves information in strict compliance with the SOW specifications on demand is developed, the consumer of control byte and number of the expert is a controller of interfaces.

At the successful end of a procedure the message of the answer always has the following format: [control byte], [the answer according to the SOW standard]. The control byte, also as earlier, defines the number of information following bytes behind it. The answer exists according to requirements of the SOW standard from heading (3 Bt), a chain of information bytes and byte of CRC.

At violation the message of the answer is sent 2-bajtnoje: [control byte], [status byte]. At the same time the MSB device is made in control byte. 4 more young people of bit form number 001 which demonstrates from that for control the only byte follows, - status byte. This situation can rather often as specifications allow a possibility not of the edition of the onboard processor of data, and also transfer of wrong data arise in case inquiry it is supported from producers of the car does not conform to the standard. The situation is also possible if the requested data are absent in random access memory of the processor of time at the moment. If the controller does not receive the expected answer, or obtains the damaged data, the MSB device of control byte is made, and is issued for control bayty the status.

At collisions in the tire the interface produces the only byte 40 conjure, existing in control byte with obnulennym in younger bit. The similar situation can arise rather often at loading of the autotire of messages above than at diagnostic data of a priority, - arithmetic establishment has to repeat initial inquiry.

Exchange according to the ISO 9141-2 protocols

ISO 9141-2 is used by most Asian and European equipment manufacturers of the car. Structure is educated the inquiry personal computer a little as differs from is used in the SOW standards that only distinction that the adapter does not need information on number of the expert and appropriately this to be present at a package should not go. Thus the inquiry from control byte and the chain of information bytes following it exists, they checksum always join. As the message of the answer the controller just transmits further the signals formed by the onboard processor. The control byte in the message of the answer is absent therefore the personal computer perceives the existing information of continuous current until the chain of a pause is not interrupted through 55 milliseconds, reporting about the termination of information package. Thus the message of the answer from one or several experts can exist according to requirements of the J1979 SOW specifications. The controller does not make the analysis of experts, throws not diagnostic experts, etc. the personal computer of own forces should not make processing of the existing data with the purpose of exarticulation of the separated experts by means of the analysis of title bytes back.

Responses to the majority of inquiries exist from the only expert.

Modifications of controllers of the latests version

All information bytes will transfer in 16-ritschnom a format (conjure).

The symbol XX appears uncertain, the withheld or not identified bytes.

The main distinctions of process of data transmission according to protocols are lower THIS and ISO 9141, is characteristic of controllers of interfaces of the latests version, and also is given a data transmission order according to the ISO 14 230 protocol:
   1) ISO 9141: The address byte Is enclosed;
   2) ISO 9141: it is carried out return not of one, and both key bytes; (the additional byte comes back also in the SOW modes, however, here it is not used).
   3) If support of the protocol is enclosed by ISO 14 230.

Association device

The order of the device of association did not change:

Departure:	20
Acceptance:	AND ON THE FOLLOWING PAGES

Choice of the protocol

The protocol appears in the next way:

VPW:
Departure:	41, 00
Acceptance:	02, 01, XX
PWM:
Departure:	41, 01
Acceptance:	02, 01, XX
ISO 9141:
Departure:	42, 02, address, where: the address - address byte (usually 33 conjure)
Acceptance:	02, K1, K2, where K1, K2 - key bytes of ISO Or: 82, XX, XX (Initializationes ISO mistakes in 9141)
ISO 14 230 (bystry Initialization):
Departure:	46, 03, R1, R2, R3, R4, R5, where: R1 ÷ R5 - the message since the beginning of request of ISO 14 230 on the association device, usually R1 ÷ R5 = C1, 33, F1, 81, 66
Acceptance:	S1, S2, … … …, where S1, S2, … … … - the message since the beginning of the answer of ISO 14 230 to the association device

More than an ECU can consistently be transferred. As the answer can be used to a negative code of the answer.

Typical affirmative answer looks the next way:

S1, S2, …. = 83, F1, 10, S1, E9, 8F, T.
ISO 14 230 (slow Initialization):

ISO 9141 is similar

Remark and notes

If use of the controller for data transmission only after some is planned by one or some of protocols, excessive components can be excluded.

For example, at the organization of the scheme under the VPW (GM) protocol in the line of connection of the controller to the car will demand only 3 sinews of the electric leading device (a clip 16, 5 and 2).

If the PWM protocol is not used, the R4, R6, R7, R8, R9, R10, T1, T2 and D1 elements can be excluded.

At refusal on exchange according to the ISO protocol of an exception elements are subject: R15, R16, R17, R18, R19, R21, T4 and T5.

The refusal on use of the VPW protocol allows to exclude the following elements: R13, R14, R23, R24, D2, D3 and T3.

Kohlen-Filmresistoren with 5 percent access of resistance are used.

Will pay attention to lack of the button of new necessary shop (RESET), - as a last resort such new shop by means of switching off of the controller of the autoplug (the new shop of the processor of interfaces automatically can be made will occur). Peresapusk of the software on the personal computer leads to repeated Initialization of the interface.