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Title: ODB protocal Post by: pico on March 18, 2008, 09:10:47 09:10 who can help me for PWM and VPW timming diagram.
Title: Re: ODB protocal Post by: alspa on May 14, 2008, 06:37:29 06:37 Pico,
The OBD2 standard allows for multiple electrical interfaces, which complicates the hardware used to interface with the vehicle. Equipment and Tool Institute has a nice interface by manufacturer page. Scantool.net also has a nice page listing vehicles and OBD2 protocols, and another describing a method of determining interface by connector pin layout. Here is a brief summary of the most popular electrical interfaces: ISO15765 (CAN) - Controller Area Network, a new higher speed interface, just now being implemented ISO9141-2 used mostly by Chrysler and the European/Asian imports ISO14230, or KWP2000 (Keyword Protocol) shares the electrical portion of ISO9141 standard, but defines it's own commands. PWM J1850-41.6 (41.6Khz Pulse Width Modulated) used mostly by Ford VPW J1850-10.4 (10.4Khz Variable Pulse Width) used mostly by GM vehicles Here is a description o fthe SAE J1850 standard http://www.interfacebus.com/Automotive_SAE_J1850_Bus.html Cheers, Alspa |