OBD-II Connector (16-pin) Symbol
Definition: The OBD-II Connector (16-pin) symbol represents the standardised SAE J1962 Data Link Connector (DLC) found in all passenger vehicles sold in the United States after 1996 and in Europe after 2001, depicted as a trapezoidal 16-pin female connector block with labelled pins including CAN H (pin 6), CAN L (pin 14), GND (pins 4/5), BATT (pin 16), and K-Line (pin 7), used in vehicle diagnostic wiring diagrams to show the interface between a scan tool and the vehicle's on-board diagnostic (OBD) system.
Also known as: OBD-II port, OBD2 connector, DLC connector, SAE J1962 connector, diagnostic port, data link connector.
What the OBD-II Connector (16-pin) symbol means
The OBD-II Connector symbol denotes the standardised 16-pin diagnostic interface through which external scan tools, data loggers, and telematics devices access a vehicle's Engine Control Units (ECUs) and fault code data. Defined by SAE J1962, this connector provides access to multiple vehicle communication protocols on specific pin assignments.
In vehicle wiring diagrams and automotive electronics schematics, the OBD-II Connector symbol conveys the interface point between the vehicle's internal CAN bus, K-Line, and other serial protocols and any external diagnostic equipment. The symbol shows the five key pins used in modern diagnostics: CAN H (pin 6), CAN L (pin 14), chassis ground GND (pins 4/5), unswitched battery power BATT (pin 16), and the legacy ISO 9141-2/ISO 14230 K-Line (pin 7).
How to identify the OBD-II Connector (16-pin) symbol
The OBD-II Connector symbol is drawn as a trapezoidal or rectangular 16-pin female connector block. Pin labels CAN H (6), CAN L (14), GND (4/5), BATT (16), and K-Line (7) are shown at the relevant positions. The trapezoidal shape with two rows of eight pins and the 'OBD-II' or 'DLC' label identify this symbol from a generic connector. The pin numbering follows the SAE J1962 standard layout.
Function in a circuit
The OBD-II Connector provides a standardised electrical interface for accessing a vehicle's diagnostic data. Pin 16 (BATT) delivers unswitched 12 V battery power to the scan tool, allowing it to operate with the ignition off. Pins 4 and 5 provide chassis and signal ground. Pins 6 and 14 carry the ISO 15765-4 CAN bus (high and low), the mandatory protocol for all vehicles since 2008 in the US. Pin 7 carries the legacy K-Line used by ISO 9141-2 and KWP2000 (ISO 14230-4) for older vehicles. The connector enables reading diagnostic trouble codes (DTCs), live sensor data (PIDs), and performing actuator tests.
Standards: IEC vs ANSI
| IEC 60617 | IEC 62196 covers vehicle charging connectors but not OBD. The OBD diagnostic interface is governed by ISO 15031 (equivalent to SAE J1979/J2012) and the specific protocol standards ISO 15765-4 (CAN), ISO 14230-4 (KWP2000), and ISO 9141-2 (K-Line). |
|---|---|
| ANSI/IEEE 315 | SAE J1962 defines the physical OBD-II DLC connector dimensions, pin assignments, and electrical requirements. SAE J1979 defines the diagnostic communication protocol (OBD service modes). J2534 defines the pass-through interface for aftermarket scan tools. |
| Key difference | The SAE J1962 standard governs the physical OBD-II connector in North America and is adopted globally; ISO 15031 is the international equivalent. There is no separate IEC connector symbol standard for OBD; the connector is drawn as a labelled multi-pin block in both IEC and ANSI/IEEE documentation. |
Terminals / pins
| Pin | Name |
|---|---|
| can_h | CAN H (6) |
| can_l | CAN L (14) |
| gnd | GND (4/5) |
| batt | BATT (16) |
| k_line | K-Line (7) |
Typical values
Pin 16 (BATT): 12 V DC unswitched, fused at 7.5–20 A. Pin 4/5 (GND): chassis and signal ground. Pin 6 (CAN H): ISO 15765-4 CAN bus, dominant = 3.5 V, recessive = 2.5 V. Pin 14 (CAN L): dominant = 1.5 V, recessive = 2.5 V. Differential CAN voltage: 2 V (dominant). Bus speed: 500 kbit/s (most vehicles) or 250 kbit/s (commercial vehicles). K-Line (pin 7): 5 V or 12 V logic, ISO 9141-2.
Where the OBD-II Connector (16-pin) symbol is used
- Automotive scan tool connections for reading and clearing diagnostic trouble codes (DTCs) from engine, transmission, ABS, and airbag ECUs
- OBD-II data loggers and telematics dongles (fleet management, insurance telematics) that plug into the DLC and transmit live PID data via Bluetooth or cellular
- Aftermarket ECU tuning interfaces (J2534 pass-through adapters) used to reprogram ECU calibration files via the OBD-II port
- Emissions inspection stations that perform OBD readiness monitor checks via the DLC to verify catalytic converter, O₂ sensor, and evaporative emission system compliance
- DIY vehicle diagnostics using low-cost ELM327-based Bluetooth/USB adapters and smartphone apps (Torque Pro, OBD Fusion)
- Automotive education and laboratory setups where students learn CAN bus communication protocols using an OBD-II breakout board
Example
In a fleet telematics installation, a Calamp LMU-3030 device plugs into the vehicle's OBD-II DLC. Pin 16 (BATT) powers the telematics unit continuously; pins 4/5 (GND) provide reference; pins 6 and 14 (CAN H/L) connect to the ISO 15765-4 CAN bus at 500 kbit/s. The unit reads live PIDs (engine RPM, vehicle speed, fuel level) every 5 seconds and transmits via 4G LTE to the fleet management cloud platform.
Key facts
- The OBD-II Connector is defined by SAE J1962 as a standardised 16-pin female trapezoidal connector mandated in all US passenger vehicles sold after January 1, 1996, and in European vehicles after 2001.
- Pin 16 provides unswitched 12 V battery power to the scan tool, allowing diagnostics with the ignition off; pins 4 (chassis GND) and 5 (signal GND) provide ground references.
- Pins 6 (CAN H) and 14 (CAN L) carry the ISO 15765-4 CAN bus, mandatory since 2008 for all OBD-II compliant vehicles in the US; CAN bus speed is typically 500 kbit/s for passenger cars.
- Pin 7 (K-Line) carries the legacy ISO 9141-2 and KWP2000 (ISO 14230-4) protocols used in older vehicles (pre-2008 European and Asian models).
- The OBD-II standard defines ten diagnostic service modes (Mode $01–$0A) for reading live data PIDs, DTCs, freeze frame data, oxygen sensor tests, and pending codes.
- The OBD-II Connector symbol in schematics shows five key pins: CAN H (6), CAN L (14), GND (4/5), BATT (16), and K-Line (7); the remaining pins (1, 2, 3, 8, 9, 10, 11, 12, 13, 15) are manufacturer-defined.
- ELM327 is the most widely used OBD-II interpreter IC; it translates OBD-II protocols (CAN, K-Line, J1850) into a simple AT command set over UART, USB, or Bluetooth.
Diagrams that use this symbol
Frequently asked questions
What does the OBD-II connector symbol mean in a wiring diagram?
The OBD-II Connector symbol represents the SAE J1962 standardised 16-pin diagnostic interface in a vehicle. It shows the connection point between the vehicle's internal CAN bus, K-Line, and power/ground lines and any external scan tool or telematics device. Defined by SAE J1962, it is mandatory in US vehicles since 1996.
What does the OBD-II connector symbol look like?
The OBD-II Connector symbol is drawn as a trapezoidal 16-pin female connector block with labelled pins: CAN H (6), CAN L (14), GND (4/5), BATT (16), and K-Line (7). The trapezoidal shape with two rows of eight pins and the 'OBD-II' or 'DLC' label distinguish it from a generic multi-pin connector in automotive schematics.
What pins are on the OBD-II connector?
Key OBD-II pins defined by SAE J1962 are: pin 4 (chassis ground), pin 5 (signal ground), pin 6 (CAN High — ISO 15765-4), pin 7 (K-Line — ISO 9141-2 / KWP2000), pin 14 (CAN Low — ISO 15765-4), and pin 16 (unswitched battery power, 12 V). Pins 1, 2, 3, 8–13, 15 are manufacturer-specific.
What protocol does the OBD-II CAN bus use?
The OBD-II CAN bus uses ISO 15765-4 (also called CAN-based OBD) at 500 kbit/s for passenger cars or 250 kbit/s for commercial vehicles. CAN H is on pin 6 and CAN L on pin 14, with a dominant differential voltage of 2 V and a recessive (idle) voltage of 2.5 V on both lines.
What is the difference between OBD-II and OBD1?
OBD1 was a pre-1996 manufacturer-specific system with non-standard connectors, protocols, and diagnostic codes varying by brand. OBD-II (mandated in the US from 1996) standardised the connector (SAE J1962), communication protocols (ISO 15765, ISO 9141, SAE J1850), and diagnostic service modes (SAE J1979), allowing any scan tool to work on any compliant vehicle.
What voltage does the OBD-II connector provide to a scan tool?
OBD-II pin 16 provides unswitched 12 V DC battery power directly to the scan tool or connected device. This power is always present regardless of ignition state. The current capacity is vehicle-fuse dependent, typically 7.5–20 A; scan tool current draw is usually under 500 mA.
What standard governs OBD-II diagnostics?
SAE J1962 defines the physical OBD-II DLC connector. SAE J1979 defines the diagnostic service modes (read DTCs, live PIDs, etc.). ISO 15031 is the international ISO equivalent of SAE J1979. The specific communication protocols are ISO 15765-4 (CAN), ISO 14230-4 (KWP2000), and ISO 9141-2 (K-Line).
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