OBD-II Pinout Diagram and 16-Pin Diagnostic Signal Map
16-pin automotive connector
Standards: SAE J1962, ISO 15031, ISO 14229
What is the OBD-II pinout?
The OBD-II Diagnostic Connector has 16 pins. Pin 1 is Vendor (reserved). Pin 2 is J1850+ (data). Pin 3 is Vendor (reserved). Pin 4 is GND (ground). Plus 12 more pins.
Standards: SAE J1962, ISO 15031, ISO 14229
Pin Assignment Table
| Pin | Signal | Type | Description |
|---|---|---|---|
| 1 | Vendor | reserved | Manufacturer specific |
| 2 | J1850+ | data | SAE J1850 Bus+ |
| 3 | Vendor | reserved | Manufacturer specific |
| 4 | GND | ground | Chassis Ground |
| 5 | GND | ground | Signal Ground |
| 6 | CAN-H | data | CAN Bus High (ISO 15765) |
| 7 | K-Line | data | ISO 9141-2 K-Line |
| 8 | Vendor | reserved | Manufacturer specific |
| 9 | Vendor | reserved | Manufacturer specific |
| 10 | J1850- | data | SAE J1850 Bus- |
| 11 | Vendor | reserved | Manufacturer specific |
| 12 | Vendor | reserved | Manufacturer specific |
| 13 | Vendor | reserved | Manufacturer specific |
| 14 | CAN-L | data | CAN Bus Low (ISO 15765) |
| 15 | L-Line | data | ISO 9141-2 L-Line |
| 16 | +12V | power | Battery Power |
Signal Types
Common Applications
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Browse more connector references →The OBD-II connector has 16 pins: Pin 1 (Vendor), Pin 2 (J1850+), Pin 3 (Vendor), and Pin 4 (GND). Plus 12 more pins. Common in Vehicle diagnostics and Emissions testing.
OBD-II Diagnostic Port Pinout
The OBD-II (On-Board Diagnostics) port is mandated on all passenger vehicles sold in the US since 1996. It provides access to the vehicle's ECU for diagnostics, real-time data logging, and emissions testing.
Wiring Tips & Best Practices
While the power (Pin 16) and ground (Pins 4 & 5) are standardized, the communication pins vary by protocol (CAN, ISO 9141, J1850). Always verify which protocol your vehicle uses before interfacing with the data lines.
Common Issues
Never short Pin 16 (Battery) to ground or data pins, as this is an unswitched 12V rail directly from the battery and can fuse your test equipment.
Why Use Interactive Diagrams?
- Accuracy: Hover over pins to see exact signal names and descriptions
- Clarity: Color-coded by signal type (power, ground, data)
- Printable: Export clean diagrams for shop floor reference