Hardware pinouts information and cables schemes

OBD-2 universal cable scheme for PWM, VPW, and ISO 9141-2 vehicles pinout

connector or cable wiring scheme

bookmark this page



This device is a CMOS microcontroller which is designed to interface a personal computer or laptop with a vehicle's On Board Diagnostic (OBD II) interface. It is intended to function with all three of the protocols used by vehicle manufacturers to implement the OBD II system as defined by SAE and ISO specifications. The OBD II system became mandatory for 1996 and up vehicles, but some vehicles were already fully or partially compatible with OBD II requirements prior to 1996. The chip is not suitable for the earlier vehicles such as OBD I. The device is intended to function as a simple scan tool and is capable of sending and receiving any OBD II message defined in SAE J1979 for any of the three types of OBDII bus implementations (PWM, VPW, ISO 9141-2). It can also be used as an inexpensive interface for custom instrumentation monitoring various vehicle parameters such as speed, RPM, coolant or intake air temperature, engine load, intake air flow rate, etc.

OBD 2 universal cable

Components:

C5, C6  .01 UF, 25V
C4      .1 UF, 25V 
C3      .47 UF, 50V 
C2,C1    20 pf, 50V 
R11, R12, R23, R9, R1, R3, R4, R25, R8  10 KOhm, 1/4 Watt 
R24 18 KOhm, 1/4 W 
R19, R18, R7, R20, R22, R5, R6, R13 1 KOhm, 1/4 W 
R21 5.6 KOhm, 1/4 W
R16, R17 510 Ohm, 1/4 W
R10 62 KOhm, 1/4 W
R15 9.1 KOhm, 1/4 W
R14 270 Ohm, 1/2 W
R2   - Not used  
D2  1N4739 Zener, 9.1V, 1W 
D1, D3  1N4148 Diode
Q3, Q4, Q5 PN2222 Transistor, NPN
Q2 PN3904 Transistor, NPN
Q1 PN3906 Transistor, PNP
IC2 7805 Regulator, 5V
IC3 LM339N Quad Comparator 
IC1 16F84-20 Microprocessor (firmware 1.07)
XTL 1 20 MHz Crystal, 20 Mhz

If you don't use PWM, you can omit R4, R6, R7, R8, R9, R10, Q1, Q2, D1.
If you don't use ISO, you can omit R15, R16, R17, R18, R19, R21, Q4, Q5
If you don't use VPW, you can omit R13, R14, R23, R24, D2, D3, Q3

Don't connect external power sources - all power direved from pin 16 of OBDII

Serial port works at 19200 baud


This information should be correct, but may be not. Please, help us to improve this document!
Is this document CORRECT or INCORRECT? Your opinion will be used to establish document status (showed at the bottom).
Related Links:
Pinouts.ru > Cars and bikes interfaces >  Pinout of OBD-2 universal cable scheme for PWM, VPW, and ISO 9141-2 vehicles and layout of 16 pin car OBD2 special connector
Document status: may be incorrect
Source(s) of this and additional information: OBD II Interface Chip Data Sheet 2 reports
Last updated at Fri Jan 11 2008. Submit additions or corrections for this document. Is this document correct or incorrect? What is your opinion?
[Discuss at the forum] [Back to index] [SUBMIT new pinout]
This page contain parts under Copyright © 2000-2007 by pinouts.ru team.
No any portion of this webpage may be reproduced in any form without visible direct link to this page provided. Webmaster permission required in any other cases.
Efforts have been made to ensure this page is correct, but it is the responsibility of the user to verify the data is correct for their application.
9138 hits since August 13, 2007