| OBD2 Diagnostic Socket (DLC) Information |
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The OBD2 Diagnostic Socket (J1962) referred to as the DLC (Diagnostic Link Connector) is now the most common type of diagnostic connector used. It can be seen fitted to most vehicles from 1996 onwards. As seen below it consists of 2 rows of 8 pins and is normally located within approximately 90 centimeters of the driver. It can be located under the steering column, in one of the kick panels or around the center console either tucked behind down by your feet or under an ashtray or cover. The DLC or OBD2 connector is wired differently depending on what vehicle the socket is fitted to. There are 5 different protocols or communication standards in use.
SAE J1850 PWM (pulse-width modulation - 41.6 kbaud, standard of the Ford Motor Company)
pin 2: Bus+ pin 10: Bus– High voltage is +5 V SAE J1850 VPW (variable pulse width - 10.4/41.6 kbaud, standard of General Motors) pin 2: Bus+ Bus idles low High voltage is +7 V Decision point is +3.5 V ISO 9141-2. This protocol has a data rate of 10.4 kbaud, and is similar to RS-232. ISO 9141-2 is primarily used in Chrysler, European, and Asian vehicles. pin 7: K-line pin 15: L-line (optional) UART signaling (though not RS-232 voltage levels) K-line idles high High voltage is Vbatt ISO 14230 KWP2000 (Keyword Protocol 2000) pin 7: K-line pin 15: L-line (optional) Physical layer identical to ISO 9141-2 Data rate 1.2 to 10.4 kbaud ISO 15765 CAN (250 kbit/s or 500 kbit/s). The CAN protocol is a popular standard and is now fitted to practically all new vehicles. pin 6: CAN High pin 14: CAN Low Note that pins 4 (battery ground) and 16 (battery positive) are present in all configurations. See next page for an OBD2 Diagnostic Test Video. This Video was taken on a 2000 Audi A3 which suffered from no communication to any control unit. The test is carried out using a Voltmeter and can quickly reveal faults such as your Diagnostic equipment will not power up or once your equipment is powered up you can not get communication with 1 or more control units. |
The Diagnostic Socket

