Wiring Diagram represents controller of interface of the personal computer with onboard system of self-diagnostics OBD II under reports of standards SAE (PWM and VPW) and ISO 9141-2 Mercedes-Benz W203 . Main destination .
To standard VPW answer wiring diagram company GM manufactures, to standard PWM - Ford, to standard ISO 9141-2 - the Asian and European models.
The considered device represents the microcontroller executed on technology (CMOS). The controller is not intended connections to onboard systems of self-diagnostics of the first generation (OBD I), as on Mercedes-Benz W203!
This wiring diagram carries out a role of the elementary scanner and is intended for reading of diagnostic codes and data of system OBD II (engine turns, temperature of a cooling fluid 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). Wiring diagram 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. The source voltage moves on the controller through 16-contact diagnostic socket OBD. Basic wiring diagram the controller for Mercedes-Benz W203 it is presented on an illustration.
Fig.1. Wiring diagram the controller of interface of the personal computer with onboard system of self-diagnostics OBD II under reports of standards SAE (PWM and VPW) and ISO 9141-2 Mercedes-Benz W203 .Recommendations about application
For connection diagram devices on Mercedes-Benz W203 the cable, length no more than 1.2 m that has special value at use of report PWM can be used not-screened. At use of a cable more lengths it is necessary to reduce resistance of resistors on a device input (R8 and R9 or R15). At use screened cable, the screen should be disconnected for the purpose of capacity drop.
The cable for connection to a serial port of the computer of Mercedes-Benz W203 also can be not-screened . The device stably works with a cable in length to 9 m. At much more length of a cable it is necessary to use more powerful communicator RS 232.
The topology of electric joints according to wiring diagram is any. At the raised moistness apply additional shunting condensers.
The free software (browser) for reading of codes and data for Mercedes-Benz W203 can be downloaded from sites of manufacture 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.
