Editing On-board diagnostics (section)

====OBD-II diagnostic connector====
[[Image:OBD 002.jpg|thumb|right|270px|Female OBD-II connector on a car]]
[[Image:OBD-II type A female connector pinout.svg|thumb|right|Female OBD-II type A connector pinout – front view]]
[[Image:OBD-II type B female connector pinout.svg|thumb|right|Female OBD-II type B connector pinout – front view. Wire placement is identical to type A, but the center groove is split in two.]]

The OBD-II specification provides for a standardized hardware interface — the female 16-pin (2x8) [[Data link connector (automotive)#OBD-II diagnostic connector|J1962 connector]], where type A is used for 12-volt vehicles and type B for 24-volt vehicles. Unlike the OBD-I connector, which was sometimes found under the bonnet of the vehicle, the OBD-II connector is required to be within {{convert|2|ft|m}} of the steering wheel (unless an exemption is applied for by the manufacturer, in which case it is still somewhere within reach of the driver).

SAE J1962 defines the pinout of the connector as:

{| class="wikitable"
|- valign="top"
!  1
| '''Manufacturer discretion'''<br>
GM: J2411 GMLAN/SWC/Single-Wire CAN.<br>
Audi: Switched +12 to tell a scan tool whether the ignition is on.<br>
VW: Switched +12 to tell a scan tool whether the ignition is on.<br>
Mercedes<ref>{{cite web |url=https://pinoutguide.com/CarElectronics/mercedes_obd2_diag_pinout.shtml |title=Mercedes PinOut |website=Pinoutguide.com |date=2019-09-30 |access-date=2022-12-27}}</ref> (K-Line): Ignition control (EZS), air-conditioner (KLA), PTS, safety systems (Airbag, SRS, AB) and some other.
!  9
| '''Manufacturer discretion'''<br>
GM: 8192 baud ALDL where fitted.<br>
BMW: RPM signal.<br>
Toyota: RPM signal.<br>
Mercedes (K-Line): ABS, ASR, ESP, ETS, BAS diagnostic.
|- valign="top"
! style="background-color: blue" |  2
| '''[[Bus (computing)|Bus]] positive Line'''<br>
[[SAE J1850]] PWM and VPW
! style="background-color: blue" | 10
| '''Bus negative Line'''<br>
SAE J1850 PWM only (not SAE 1850 VPW)
|- valign="top"
! 3
| '''Manufacturer discretion'''<br>
Ethernet TX+ (Diagnostics over IP)<br>
Ford DCL(+) Argentina, Brazil (pre OBD-II) 1997–2000, USA, Europe, etc.<br>
Chrysler CCD Bus(+)<br>
Mercedes (TNA): TD engine rotation speed.
! 11
| '''Manufacturer discretion'''<br>
Ethernet TX- (Diagnostics over IP)<br>
Ford DCL(-) Argentina, Brazil (pre OBD-II) 1997–2000, USA, Europe, etc.<br>
Chrysler CCD Bus(-)<br>
Mercedes (K-Line):&nbsp;Gearbox and other transmission components (EGS, ETC, FTC).
|- valign="top"
! style="background-color: gray" |  4
| '''Chassis ground'''
! 12
| '''Manufacturer discretion'''<br>
Ethernet RX+ (Diagnostics over IP)<br>
Mercedes (K-Line):&nbsp;All activity module (AAM), Radio (RD), ICS (and more)
|- valign="top"
! style="background-color: gray" |  5
| '''Signal ground'''
! 13
| '''Manufacturer discretion'''<br>
Ethernet RX- (Diagnostics over IP)<br>
Ford: FEPS – Programming PCM voltage<br>
Mercedes (K-Line):&nbsp;AB diagnostic – safety systems.
|- valign="top"
! style="background-color: lime" |  6
| '''CAN high'''<br>
(ISO 15765-4 and SAE J2284)
! style="background-color: lime" | 14
| '''CAN low'''<br>
(ISO 15765-4 and SAE J2284)
|- valign="top"
! style="background-color: yellow" |  7
| '''K-line'''<br>
(ISO 9141-2 and ISO 14230-4)
! style="background-color: yellow" | 15
| '''L-line'''<br>
(ISO 9141-2 and ISO 14230-4)
|- valign="top"
!  8
| '''Manufacturer discretion'''<br>
Activate Ethernet (Diagnostics over IP)<br>
Many BMWs: A second K-line for non OBD-II (Body/Chassis/Infotainment) systems.<br>
Mercedes: Ignition<br>
! style="background-color: red" | 16
| '''Battery voltage'''<br>
(+12 Volt for type A connector)<br>
(+24 Volt for type B connector)
|}

The assignment of unspecified pins is left to the vehicle manufacturer's discretion.<ref>{{cite web |url=https://pinoutguide.com/CarElectronics/car_obd2_pinout.shtml |title=OBD II diagnostic interface pinout |website=Pinoutguide.com |date=2017-12-02 |access-date=2022-06-28}}</ref>