OBD-II 通讯协议 OBD-II Network Standards » J1850 PW – Adopted by GM; also known as Class 2. – Adopted by Chrysler (known as J1850). – Some references to PW mode heard about in regards to Toyota (and Honda ?). – 10.4 kbps, single wire. » J1850 PWM – Adopted by Ford; also known as Standard Corporate Protocol (SCP). – Also seen in some Mazda products. – Some references to PWM mode heard about in regards to Mitsubishi. – 41.6 kbps, two wire balanced signal. » ISO 9141 and ISO 9141-2 (also known as ISO 9141 CARB) – Seen in some Chrysler and Mazda products. – Seems to be more common in Europe. – 10.4 kbps, single wire. OBDII 通讯协议 obdii generic communication protocols by manufacturer Recently I tried to install my product on Peuzeot(406 or something similar). There was KWP 2000 bus. I tried to get the speed alue from the bus by sending the following string 0xc2 0x33 0xf1 0x01 0x0d 0xf4. On responce I receied two answers from 2 different ECUs: 1) 0x83 0xf1 0x10 0x7f 0x01 0x12 0x16 1) 0x83 0xf1 0xa4 0x41 0x0d 0x00 0x66 The first ECU sent me NACK (This response code indicates that the requested action will not be taken because the serer (ECU) does not support the arguments of the request message or the format of the argument bytes do not match the prescribed format for the specified serice.) My question is: if there was something wrong with the arguments of the request message, the second ECU also should not understand the request, bit it did ! And the second question is: why the first ECU did send the negatie answer. If you look at the j1979 PDF you will find there that "If an ECU does not support any of the PIDs requested it is not allowed to send a ...
