Subaru Legacy/Outback

1999-2003 of release

Repair and car operation



Subaru Legasi, Autbek
+ Cars Subaru Legacy, Outback
+ The operation manual
+ Routine maintenance
+ The engine
+ Systems of cooling, heating
- The power supply system and release
   Specifications
   + System of injection of fuel
   - Control systems of the engine and decrease in toxicity of the fulfilled gases
      ЕСМ - check of serviceability of a condition and replacement
      Diagnostics of malfunctions - the general information and preliminary checks
      System of onboard self-diagnostics (OBD) - the general information
      Application of an oscillograph for supervision of working parametres of a control system
      Removal and installation of components of systems of decrease in toxicity of the fulfilled gases
   + System of release of the fulfilled gases
+ Engine electric equipment
+ Manual box and differential
+ Automatic transmission
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment


To learn more Server Data Recovery Services Westchester on site


System of onboard self-diagnostics (OBD) - the general information

 On the models equipped with system OBD II, on established under a cowl шильде there should be a record «OBD II compliant», and diagnostic socket DLC should be 16-contact. As a rule, system OBD II necessarily equips the models intended for the North American market, since 1996 вып., and also the European models, since 2000 вып.


The general description of system OBD

Problem of any onboard system of self-diagnostics (OBD) is revealing of refusals and infringements of functioning of under control systems with entering in memory of the processor of corresponding diagnostic codes (DTC) and the notification of the driver about the infringement fact (usually by means of built in in a combination of devices of a control lamp of refusals MIL / «Check up the engine»).

Besides code DTC in memory ECM it is fixed also current working parametres of the engine at the moment of infringement revealing.

At infringement of serviceability of functioning of the information gauges which are taking part in managerial process by the engine, ECM can make switching of systems in emergency operation. The base working parametres providing adequate work of the engine are thus activated (some absolute pseudo-signal of the faulty gauge is feigned directly by the management module), however with inevitable decrease in efficiency of its return and expense increase топилва, - the car should be driven away on a car repair shop for the purpose of revealing and elimination of causes of a failure.

System OBD structure includes some the diagnostic devices making monitoring of separate parametres of systems of decrease of 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 gauges and actuation mechanisms, supervises operational cycles of a vehicle, provides possibility of freezing of parametres and clearing of the block of memory.

Models considered in the present Management can be completed as system of onboard diagnostics of the second generation of standard SAE (OBD II), and firm system OBD of standard Subaru (some of models 2.0 and 2.5). The Basic element of any system OBD is the onboard processor, more often named the electronic module of management (ECM). ECM is a brain of a control system of the engine. The initial data arrives on the module from various information gauges and other electronic components (switches, the relay etc.), and also signals registered OBD refusals and infringements. Codes of the registered malfunctions are fixed in memory of the processor.

Data read-out of memory of processor OBD is made by means of the special scanner (standard SAE - GST or Subaru - SSM), reading of a database connected to a 16-contact diagnostic socket (DLC), located under the panel of devices from the driver's party of the car.

 Reading of codes DTC on models with OBD II is possible with the help both GST, and SSM, on models with OBD Subaru - only by means of monitor SSM.


On service of components of control systems by the engine/decrease of toxicity of the fulfilled gases special guarantee certificates with the prolonged period of validity extend. It is not necessary to undertake attempts of independent performance of problem diagnostics ECM or replacement of components of system, to an exit of terms of the given obligations, - address to experts of firm car repair shops of company Subaru.

Data on diagnostic devices

Check of serviceability of functioning of components of control systems by the engine and decrease in toxicity of the fulfilled gases can be made by means of a universal digital measuring instrument (multimeter). Use of a digital measuring instrument preferably for the several reasons. First, on analogue devices it is difficult enough (at times, 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 high enough impedance (internal resistance of the device makes 10 million Ohm). As the voltmeter is connected to a checked chain in parallel, accuracy of measurement by that above, than the smaller parasitic current will pass through actually device. The given factor is not essential at measurement concerning high values of pressure (9 ÷ 12), however there is defining at diagnostics of elements giving out low-voltage signals, such, as, for example, a ljambda-probe where it is a question of measurement of shares of volt.


Parallel supervision of parametres of signals, resistance and pressure in all chains of management is possible by means of a splitter included consistently in a socket of the module of management (ECM). Measurement of parametres of signals on splitter plugs in various modes of functioning of the engine allows to define a current condition of the last and to reveal taking place infringements.

At diagnostics of electronic control systems by the engine, transmission, ABS and SRS special scanners of standard SAE (GST), - OBD II, - or firm scanner Subaru Select Monitor (SSM), - OBD standard Subaru are applied. Many scanners SAE of the second generation (OBD II) are multipurpose, at the expense of possibility of change of a cartridge depending on model of the diagnosed car (Ford, GM, Chrysler, etc.), others are adhered to requirements of the regional authorities and intended for use in certain areas of the world (Europe, Asia, the USA etc.). Scanner connection is made to the onboard diagnostic socket DLC which appointment of conclusions is explained on an illustration.

 Connection attempts to socket DLC of the scanners which are distinct from GST OBD II or SSM it is fraught with failure of a contour of connection of monitor SSM!


Models 2.0 and 2.5 l

1

A food from the battery

2

It is not used

3

It is not used

4

Signal from ECM to scanner SSM

5

Signal from scanner SSM to ECM

6

Clock signal SSM

7
It is not used
8
It is not used
9
It is not used
10
Line К-Line ISO 9141 CARB
11
It is not used
12
Grounding
13
Grounding
14
It is not used
15
It is not used
16
It is not used

L models 3.0

1

A food from the battery

2

It is not used

3

It is not used

4

It is not used

5

It is not used

6

Clock signal SSM 1

7
It is not used
8
Clock signal SSM 2
9
It is not used
10
Line К-Line ISO 9141 CARB
11
It is not used
12
Grounding
13
Grounding
14
It is not used
15
It is not used
16
It is not used

One more way of data read-out OBD is connection to system of the personal computer equipped with a special cable and equipped with software OBD.

 More detailed information to data read-out by means of scanners can be learnt on sites www.obdii.com, www.obd-2.com and www.obd-2.de.


Universal adapter K-L-Line serves for the coordination of signals of port RS-232 and interfaces ISO-9141 (K-Line) and ALDL. The various cables can be connected To adapter sockets, allowing to make data read-out OBD from cars of various marks. The switches provided on the adapter and indication elements allow to choose necessary operating modes and approximately to estimate quality of functioning of target lines. So, the luminescence of a green light-emitting diode with marks L-Line testifies to connection of line L with weight of the car. Activation of a red light-emitting diode with marks К-Line confirms about presence on a line To in a present situation of time of high potential. At the established communication with system OBD of the car the blinking of indicators can be imperceptible for an eye in view of high speed of data exchange. Connection to the computer is made directly in a 25-contact CATFISH-PORT or in a 9-contact CATFISH-PORT by means of transitive cable RS232 25-9.


Some input readers besides usual diagnostic operations allow at connection to the personal computer to make распечатывание stored in memory of the module of management basic schemes of the various equipment (if those are put in ECM), to program anticreeping system and blocks of management of various devices of the car, and also in real time to observe signals in electric chains of the car.

On some models reading brought in memory of system OBD of codes DTC can be made also with the help built in in an instrument guard of the car of a control lamp of refusals MIL / «Check up the engine», - see more low.

Reading of codes DTC

 More detailed information on reading of codes of malfunctions is led in the user's guide to the scanner. The list of codes of malfunctions is led in the Specification to the present Chapter.


Schemes of an arrangement of interactive components used on cars of systems of onboard diagnostics considered in the present Management are presented on illustrations.

The scheme of an arrangement of interactive components of system of onboard diagnostics on the models equipped with system of onboard self-diagnostics OBD II

1 — ECM
2 — the Control lamp of refusals MIL / «Check up the engine»
3 — the Socket of a mode of testing

4 — Diagnostic socket DLC (under SSM or GST)


The scheme of an arrangement of interactive components of system of onboard diagnostics on models 2.0 and 2.5 l equipped OBD Subaru

1 — ECM
2 — the Control lamp of refusals MIL / «Check up the engine»
3 — the Socket of data read-out from memory of the processor

4 — the Socket of a mode of testing
5 — Diagnostic socket DLC


The models equipped OBD II

With application of scanner SSM included in a normal mode (Subaru)

In the main menu (MAIN MENU) on the display screen choose point {Each System Check} and press a key «YES».

In the field {System Select Menu} choose a bookmark {Engine Control System} and again press «YES».

After a conclusion to the screen of the data about engine type, press «YES» once again.

In the field {Engine Diagnosis} choose point {Diagnostic Code (s) Display} and press «YES».

Further choose the subparagraph {Current Diagnostic Code (s)}, or {History Diagnostic Code (s)}. Confirm a choice with key pressing «YES» and make reading of displayed codes DTC.

With application of scanner SSM included in mode OBD (SAE)

In the main menu (MAIN MENU) on the display screen choose point {2. Each System Check} also press a key «YES».

In the field {System Select Menu} choose a bookmark {Engine Control System}. And again press «YES».

After a conclusion to the screen of the data about engine type, press «YES» once again.

In the field {Engine Diagnosis} choose point {OBD System} and press «YES».

In the menu {OBD Menu} choose point {Diagnostic Code (s) Display}, press «YES» and make sure of a conclusion of codes DTC to the monitor screen.

With scanner GST application (SAE)

Operate according to instructions put to the scanner.

The models equipped OBD Subaru


With scanner SSM application

Operate according to instructions.

Without scanner SSM application (on a control lamp of refusals MIL / «Check up the engine»)

Switch off ignition and connect a socket of data read-out from memory of the processor.

Include ignition. If at ignition inclusion control lamp MIL is activated, pass to a following stage of check, otherwise check up on presence of breakages and short circuits electroconducting of giving of a food and grounding ECM, and also electroconducting of lamp MIL. Make necessary corrections.

Make sure of serviceability выcandlesивания a control lamp of refusals of a code of malfunction (DTC). Copy the identified codes, then switch off ignition and disunite a data read-out socket.

The control lamp of refusals (MIL) highlights codes DTC brought in memory ECM in the form of sequence of gleams of various length. Thus long gleams (duration of an order of 1.3 seconds) designate decimal categories of a code, short (duration nearby 0.2) - individual categories, sequence of gleams in 0.5 seconds correspond to a code of absence DTC in memory of the processor.


The information maintenance of categories of a 5-digit code of kind P0380

Categories of a code of kind Р 0 3 8 0 have following value (from left to right):

Category 1

P — the Power unit
B — the Body
With — the Chassis

Category 2 a code Source

0 — Standard SAE
1 — Expanded - set by the manufacturer

Category 3 System

0 — System as a whole
1 — System подмешивания air (Air/Fuel Induction)
2 — System of injection of fuel
3 — System ignition ignitions/admissions
4 — System additional the release control
5 — Speed of the car and management of turns х/х
6 — Entrance and target signals of the module of management
7 — Transmission

Categories 4 and 5

Serial number of malfunction of a component or chain 00-99

Procedure of general diagnostics of the car

 More detailed information on reading of codes of malfunctions is led in the user's guide to the scanner. The list of codes of malfunctions is led in Specifications to the present Chapter.


The models equipped OBD II

Preparation

Lift the car over the earth, or tyre out it on the roller stand.

 Remember that during check all four wheels of the car will rotate, - track, that near to wheels there were no tools and extraneous subjects!


Check with scanner SSM application

 After end of check and clearing of memory of the processor make sure of absence remained not identified the data.


Take from a small suitcase scanner SSM and connect to it a diagnostic cable. Fill in the scanner a working cartridge.


Connect halves located at the left under the panel of devices of a socket of a mode of testing.

Connect SSM to located also at the left under the panel of devices to diagnostic socket DLC.

 Socket DLC is intended for connection only scanners of type SSM or GST OBD-II!


Include ignition (the engine do not start), then include a scanner food.


In the main menu (MAIN MENU) on the display screen choose point {Each System Check} and press a key «YES».

In the field {System Select Menu} choose a bookmark {Engine Control System}. And again press «YES».

After a conclusion to the screen of the data about engine type, press «YES» once again.

In the field {Engine Diagnosis} choose point {Dealer Check Mode Procedure} and press «YES».

After a conclusion to the screen of the monitor of a question «Perform Inspection (Dealer Check) Mode?» Enter acknowledgement, also by pressing a key «YES».

Further operate according to displayed instructions. If after procedure end in memory of the processor will remain any DTC, the corresponding information will be displayed the monitor.

Release a lay brake, - the difference in frequency of rotation of forward and back wheels can be at the bottom of operation of control lamp ABS, however it is not necessary to consider as an infringement sign, - after end of procedure of diagnostics of a control system by the engine do not forget to remove from memory of the processor a code of malfunction ABS.

Check with scanner GST application

 After end of check and clearing of memory of the processor make sure of absence remained not identified the data.


Connect halves located at the left under the panel of devices of a socket of a mode of testing.

Connect GST to located also at the left under the panel of devices to diagnostic socket DLC.

 Socket DLC is intended for connection only scanners of type SSM or GST-OBD II!


Start the engine, - preliminary make sure that selector AT lever is in position «Р».

By means of the selector/gear change lever activate gauges-switches of positions «Р» and «N» transmissions.

For activation of the gauge-switch of stoplights squeeze out a pedal of a foot brake.

Within nearby 40 seconds keep frequency of rotation of the engine in a range 2500 ÷ 3000 rpm.

 On models without the built in tachometre take advantage of a tachometre with inductive connection.


Translate the selector lever in position «D» and establish speed of movement 5 ÷ 10 km/h (3 ÷ 6 miles/ch).

 On models AWD do not forget to release a lay brake, - the difference in frequency of rotation of forward and back wheels can be at the bottom of operation of control lamp ABS, however it is not necessary to consider as an infringement sign, - after end of procedure of diagnostics of a control system by the engine do not forget to remove from memory of the processor a code of malfunction ABS.


By means of scanner GST consider and copy brought in memory of the processor codes of malfunctions (DTC).

The models equipped OBD Subaru


Check with scanner SSM application

Operate according to the instructions resulted in subsection Check with application of scanner SSM above.

Check without scanner SSM application

 On models AWD do not forget to release a lay brake, - the difference in frequency of rotation of forward and back wheels can be at the bottom of operation of control lamp ABS, however it is not necessary to consider as an infringement sign, - after end of procedure of diagnostics of a control system by the engine do not forget to remove from memory of the processor a code of malfunction ABS.


Start the engine and warm up it to normal working temperature.

Switch off ignition and include neutral transfer (models with РКПП) / translate the selector lever in position «Р» (models with АТ).

Connect halves of a socket of a mode of testing (it is painted in green colour), then include ignition, - if there was an activation of a control lamp of refusals (MIL), pass to a following stage of check, otherwise check up on presence of breakages and short circuits electroconducting of giving of a food and grounding ECM, and also electroconducting of lamp MIL. Make necessary corrections.

On models with АТ translate the selector lever in position «N», then in «Р».

Start the engine and copy codes highlighted by control lamp MIL. If the lamp does not highlight any codes, pass to a following stage of check.

Minimum for one minute disperse the car till the speed of 11 km/h (7 miles/ch).

Lift frequency of rotation of the engine to value over 2000 rpm. Copy codes highlighted by lamp MIL, - if no codes are deduced by a lamp, hence, refusal has other reason.

Clearing of memory of system of self-diagnostics

 More detailed information on reading of codes of malfunctions is led in the user's guide to the scanner.


The models equipped OBD II

With application of scanner SSM included in a normal mode (Subaru)

In the main menu (MAIN MENU) on the display screen choose point {2. Each System Check} also press a key «YES».

In the field {System Select Menu} choose a bookmark {Engine Control System}. And again press «YES».

After a conclusion to the screen of the data about engine type, press «YES» once again.

In the field {Engine Diagnosis} choose point {Clear Memory} and press «YES».

After on the monitor screen messages «Done» and «Turn Ignition Switch OFF» will be deduced, switch off the scanner, then turn a key in the ignition lock in position OFF.

 On models 2.0 and 2.5 l after end of clearing of memory of the processor are necessary to make initialization of the electromagnetic valve of stabilisation of turns of idling (IAC), - turn a key in position ON and, before to carry out engine start, wait not less than 3 seconds.


With application of scanner SSM included in mode OBD (SAE)

In the main menu (MAIN MENU) on the display screen choose point {2. Each System Check} also press a key «YES».

In the field {System Select Menu} choose a bookmark {Engine Control System}. And again press «YES».

After a conclusion to the screen of the data about engine type, press «YES» once again.

In the field {Engine Diagnosis} choose point {OBD System} and press «YES».

In the menu {OBD Menu} choose point {4. Diagnosis Code (s) Cleared}, press «YES».

After a conclusion to the inquiry screen «Clear Diagnosis Code?» Enter acknowledgement by key pressing «YES», then switch off a food of the scanner and ignition.

 On models 2.0 and 2.5 l after end of clearing of memory of the processor are necessary to make initialization of electromagnetic valve IAC.


With scanner GST application (SAE)

Operate according to instructions put to the scanner. On models 2.0 and 2.5 l do not forget to make valve IAC initialization.

The models equipped OBD Subaru


With scanner SSM application


Operate according to the instructions resulted above.

Without scanner SSM application (on a control lamp of refusals MIL / »Check up the engine»)

Switch off ignition and include neutral transfer (models with РКПП) / translate the selector lever in position «Р» (models with АТ).

Connect halves of a socket of a mode of testing (it is painted in green colour), then include ignition, - if there was an activation of a control lamp of refusals (MIL), pass to a following stage of check, otherwise check up on presence of breakages and short circuits electroconducting of giving of a food and grounding ECM, and also electroconducting of lamp MIL. Make necessary corrections.

On models with АТ translate the selector lever in position «N», then in «Р».

Start the engine and a minimum for one minute disperse the car till the speed of 11 km/h (7 miles/ch).

Lift frequency of rotation of the engine to value over 2000 rpm. Copy codes highlighted by lamp MIL and make necessary regenerative repair (the list of codes DTC is resulted in Specifications).

Switch off ignition and disunite a socket of a mode of testing.

Connection of the personal computer to onboard system of self-diagnostics OBD II by means of the interface controller BR16F84-1.0 under reports of standards SAE (PWM and VPW) and ISO 9141-2

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

Standard VPW is answered with models of manufacture of company GM, PWM - Ford, ISO 9141-2 - the Asian and European models.


The general data

The scheme of the organisation of connection is presented on an illustration.


The considered device represents the microcontroller executed on technology КМОП (CMOS). The device plays a role of the elementary scanner and is intended for reading of diagnostic codes and the data of system OBD II (engine turns, temperature of a cooling liquid and soaked up air, loading characteristics, the expense of air arriving in the engine, etc.) within the limits of standard SAE J1979 through the tyre of any execution (PWM, VPW and ISO 9141-2).

Main destination

To the computer it is enough for connection 3-zhilnogo a wire, connection to a diagnostic socket is carried out 6-zhilnym by a wire. Pressure of a food moves on the controller through 16-contact diagnostic socket OBD.

Recommendations about application

For device connection to the car than 1.2 m that has special value at use of report PWM can be used неэкранированный a cable, length no more. At cable use большей lengths it is necessary to reduce resistance of resistors on a device input (R8 and R9 or R15). At use экранированного a cable, the screen should be disconnected for the purpose of capacity decrease.

The cable for connection to a computer serial port also can be неэкранированным. The device stably works with a cable in length to 9 m. At much большей to length of a cable it is necessary to use more powerful коммуникатор RS 232.

The topology of electric connections is any. At the raised humidity apply additional shunting condensers.

The free software (browser) for reading of codes and the data can be downloaded from sites of manufacturers or a site of our publishing house arus.spb.ru and is intended for use under DOS. The insignificant size of a program application in a variant «under DOS» allows to contain it on loading diskette DOS and to use even on the computers equipped incompatible with DOS with the software. An unessential condition is even presence in the hard disk computer.

The general principles of data exchange

 If the opposite is not stipulated especially, all numbers are resulted in 16-richnom a format (hex). The decimal format is designated by a label dec.


Data exchange goes on three-wire consecutive connection without application инициализационного an exchange of office messages (handshaking). The device listens to the channel on presence of messages, executes accepted commands and transfers results to the personal computer (PC) then immediately comes back in a listening mode. Entering into the controller and the data starting with it are organised in the form of a chain of bytes consistently going one after another, first of which is control. The obychnokontrolnyj byte represents number from 0 to 15 dec (in decimal calculation) (or 0-F hex), describing quantity of information bytes following further. So, for example, 3-bajtnaja the command will look as follows: 03 (control byte), 1st byte, 2nd byte, 3rd byte. The similar format is used as for entering commands on interrogation of onboard system of self-diagnostics, and for the outgoing messages containing the requested information. It is necessary to notice that in control byte four younger bits are used only, - the senior bits are reserved under some special commands and can be used PC at initialization of connection with the controller and the coordination of the report of data transmission, and also the controller for the control of errors of transfer. In particular, in case of an error by transfer, the controller makes installation of the senior meaning bit (MSB) control byte in unit. By successful transfer all four senior bits are established in a zero.

 There are separate exceptions to the rules of use of control byte.


Initialization of the controller and onboard system of self-diagnostics

To start data exchange PC should make installation of connection with the controller, then initialize the controller and the channel of data OBD II.

Connection installation

After controller connection to PC and to diagnostic socket OBD its initialization for the purpose of prevention of the "lags" connected with noise in consecutive lines in a case if their connection should be made has been made before inclusion of a food of the controller. The elementary check of activity of the interface is simultaneously made. First of all the one-byte signal 20 hex, perceived by the controller as a command on connection installation is sent. In the answer the controller instead of the control sends unique byte FF hex (255 dec) and passes in a mode of expectation of reception of the data. Now PC can pass to initialization of the channel of the data.

 The case in point is one of the few when the controller does not use control byte.


Initialization

At the given stage report initialization on which data exchange will be made, and in case of report ISO – initialization of onboard system is made. Data exchange is made on one of three reports: VPW (General Motors), PWM (Ford) and ISO 9141-02 (the Asian/European manufacturers).

 There is a set of exceptions: so, for example, at interrogation of some models of cars Mazda it can be used «фордовский» report PWM. Thus, at occurrence of problems of transfer it is necessary first of all to try to take advantage of any other report. The report choice is made by transfer of the combination consisting of control byte 41 hex and the following is direct behind it of the byte defining type of the report: 0 = VPW, 1 = PWM, 2 = ISO 9141. So, for example, at the command of 41 02 hex initialization of report ISO 9141 is made.


In the answer the controller sends control byte and condition byte. Installation MSB of control byte speaks about presence of the problems, the byte of a condition thus following it will contain the corresponding information. At successful initialization the control byte 01 hex, specifying that follows further верификационный condition byte is sent. In case of reports VPW and PWM верификационный the byte represents a simple echo of byte defining the report (0 or 1, accordingly), at initialization of report ISO 9141 it will be the digital key returned by onboard processor OBD and defining which of two versions of the report slightly different from each other will be used.

 The digital key has purely information appointment. It is necessary to notice that initialization of reports VPW and PWM occurs much faster as demands only transfer of the corresponding information to the controller. On the models answering to standard ISO, initialization occupies an order of 5 seconds spent for an information exchange of the controller with the onboard processor, made with a speed 5 бод. It is necessary to pay attention of the reader that on some models of cars of family ISO 9141 initialization of the report stops, if the inquiry about delivery of the data is not transferred during a 5-second interval, - told means that PC should make automatic delivery of inquiries everyone some seconds, even in a single mode.


After installation of connection and report initialization the regular data exchange, consisting of arriving from PC inquiries and answers given out by the controller begins.

Data exchange order

Controller functioning at use of reports of family ISO 9141-2 and SAE (VPW and PWM) occurs under a little various scenarios.

Exchange under reports SAE (VPW and PWM)

At data exchange under the given reports there is a buffering only one shot of the data that means necessity of a concrete definition subject to capture or shot return. In some (rare) cases the onboard processor can transfer the packages consisting more than from one shot. In such situation the inquiry should repeat until all shots of a package will not be accepted.

The inquiry always is formed as follows: [Control byte], [Inquiry under standard SAE], [shot Number]. As already it was mentioned above, the control byte usually represents the number equal to full quantity of bytes following it. The inquiry is made out according to Specifications SAE J1950 and J1979 and consists of heading (3 bytes), sequence of information bytes and byte of the control of an error (CRC). We will notice that while the information on demand is formed in strict conformity with Specifications SAE, the consumer of control byte and shot number is the interface controller.

At successful end of procedure the reciprocal message always has the following format: [Control byte], [the Answer under standard SAE]. The control byte, as well as earlier, defines quantity of information bytes following it. The answer according to requirements of standard SAE consists of heading (3 bytes), a chain of information bytes and byte CRC.

At failure it is sent 2-bajtnoe the reciprocal message: [Control byte], [condition Byte]. Thus in control byte installation MSB is made. Four younger bits form number 001, testifying that the control is followed by unique byte, - condition byte. The given situation can arise often enough as Specifications suppose possibility of a lack of distribution the onboard processor of the data, and also transfer of the incorrect data to a case when the inquiry does not correspond supported by manufacturers of the car to the standard. The situation when the required data is absent in operative memory of the processor in time present situation is possible also. When the controller does not receive the expected answer, or obtains the damaged data, installation MSB of control byte is made, and after the control the condition byte stands out.

At collisions in the tyre the interface develops unique byte 40 hex, being in control byte with the nulled younger bit. The similar situation can arise often enough at loading of an automobile tyre by messages of higher than at the diagnostic data of a priority, - the computer should repeat initial inquiry.

Exchange under reports ISO 9141-2

Standard ISO 9141-2 is used by the majority of the Asian and European manufacturers of automobile technics. The structure formed PC inquiry a little than differs from used in standards SAE, with that only a difference that the controller does not require the information on number of a shot and corresponding given to be present at a package should not. Thus, the inquiry always consists of control byte and a chain of the information bytes including the control sum following it. As the reciprocal message the controller simply relays the signals generated by the onboard processor. The control byte in the reciprocal message is absent, therefore PC perceives the arriving information a continuous stream until the chain does not interrupt a pause in 55 milliseconds, informing on end of an information package. Thus, the reciprocal message can consist of one or more shots according to requirements of specifications SAE J1979. The controller does not make the analysis of shots, does not reject not diagnostic shots etc. PC should make own forces processing of the arriving data for the purpose of exarticulation of separate shots by the analysis of heading bytes.

 Answers to the majority of inquiries consist of a unique shot.

The updatings made in the interface controllers of last versions

 All information bytes are transferred in 16-richnom a format (hex).

The symbol XX means the uncertain, reserved or neolearnt byte.


The basic differences of process of data transmission under reports SAE and ISO 9141, characteristic for the interface controllers of last versions, and also a data transmission order under report ISO 14230 are more low resulted:

1) Standard ISO 9141: the address byte Is added;
2) Standard ISO 9141: return not one, and both key bytes (the additional byte comes back also in modes SAE, however here it is not used) Is carried out;
3) support of report ISO 14230 Is added.

Connection installation

The order of installation of connection has not changed:

Sending: 20
Reception: FF

Report choice

The report gets out in as follows:
VPW:
Sending: 41, 00
Reception: 02, 01, XX
PWM:
Sending: 41, 01
Reception: 02, 01, XX
ISO 9141:
Sending: 42, 02, adr, where: adr - address byte (usually 33 hex)
Reception: 02, К1, К2, where К1, К2 - key bytes ISO
Or:
82, XX, XX (an error of initialization ISO 9141)
ISO 14230 (fast initialization):
Sending: 46, 03, R1, R2, R3, R4, R5, where: R1 ÷ R5 - the message on the beginning of inquiry ISO 14230 on connection installation, usually R1 ÷ R5 = С1, 33, F1, 81, 66
Reception: S1, S2, … … …, where S1, S2, … … … - the message on the beginning of answer ISO 14230 on connection installation

 Can be transferred consistently more than one ECU. As the answer the negative code of the answer can be used.

The typical affirmative reply looks as follows: S1, S2, … …. = 83, F1, 10, С1, Е9, 8F, BD
ISO 14230 (slow initialization):
Similarly ISO 9141

The remark and comments

If use of the controller for data transmission only on any one is planned or to two of reports, superfluous components can be excluded. For example, at the scheme organisation under report VPW (GM) in a wire of connection of the controller to the car three veins of electroconducting (the plug 16, 5 and 2) be required only.

If report PWM is not used, elements R4, R6, R7, R8, R9, R10, Т1, Т2 and D1 can be excluded.

At refusal of an exchange under report ISO elements are subject to an exception: R15, R16, R17, R18, R19, R21, Т4 and Т5.

Refusal of use of report VPW allows to exclude following elements: R13, R14, R23, R24, D2, D3 and Т3.

Ugolno-film resistors with the 5 percent admission of resistance are applied.

Pay attention to absence of the button of emergency reboot (RESET), - in case of need such reboot can be made by a detachment of the controller from an automobile socket (reboot of the interface processor will occur automatically). Software restart on PC leads to repeated initialization of the interface.

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