The Data Link Connector (DLC), commonly known as the OBD2 port, is a crucial component for diagnosing and troubleshooting vehicle issues. This article provides a comprehensive pinout diagram for the DLC 3 OBD2 connector, specifically focusing on GM vehicles and their transition from J1850 protocols to the CAN bus system. Understanding this pinout is essential for anyone working with vehicle diagnostics, especially when using devices requiring an HDMI connection, although such a connection is non-standard for OBD2. Adapters might exist that convert DLC 3 data to a visual format viewable via HDMI, but these would utilize custom pinouts not covered by standard OBD2 documentation.
Decoding the DLC 3 OBD2 Pinout
The DLC 3 connector, a 16-pin trapezoidal connector, is the standard for OBD2 systems in most vehicles. Here’s a breakdown of the pin assignments for GM vehicles:
| Pin Number | Pin Name | Description |
|---|---|---|
| 1 | Low Speed GMLAN Serial Data | Used for communication between various modules like the amplifier, rear seat audio, vehicle communication interface module (VCIM), and more. |
| 2 | J1708 | SAE J1708 Serial Data (Primarily for trucks) |
| 3 | PTLAN (+) | High-speed hybrid GMLAN serial data bus positive terminal (for hybrid vehicles) |
| 4 | GND | Chassis Ground |
| 5 | SGND | Signal Ground |
| 6 | HS-CAN (+) | High-Speed CAN bus positive terminal; critical for communication between modules like BCM, ECM, TCM. |
| 7 | KW200/J1708 | Keyword 2000 Serial Data (some models) / SAE J1708 Serial Data A (Trucks) |
| 8 | Diagnosis Enable | Central Control Module Diagnosis Enable (specific Holden models) |
| 11 | PTLAN (-) | High-speed hybrid GMLAN serial data bus negative terminal (for hybrid vehicles) |
| 14 | HS-CAN(-) | High-Speed CAN bus negative terminal. |
| 15 | J1708 B | SAE J1708 Serial Data B (Primarily for trucks) |
| 16 | Battery+ | Battery Positive Voltage |
Pre-2000 GM OBD2 Pinout (May Vary):
Older GM vehicles (pre-2000) utilized a different pinout configuration:
| Pin | Wire Color | Function |
|---|---|---|
| 2 | PPL | Serial Data Signal-Class B |
| 4 | BLK | Ground |
| 5 | BLK/WHT | VCM Ground |
| 8 | BLK/WHT | Keyless Entry Program Enable Signal |
| 9 | TAN | SIR Serial Data |
| 12 | TAN/WHT | Diagnostic Signal (ABS)/(15,000 GVW Only) |
| 13 | ORN | Diagnostic Signal-Transfer Case Control Module |
| 14 | GRN DK | Diagnostic Signal-Entertainment and Comfort |
| 16 | ORN | Battery |
Evolution of GM OBD2 Protocols: J1850 to CAN
GM vehicles transitioned from the J1850-VPW (Variable Pulse Width) protocol to the Controller Area Network (CAN) bus system.
- J1850-VPW: Primarily used in GM vehicles from 1996 to 2003. This single-wire communication system had limitations in bandwidth and speed.
- CAN Bus: Became prevalent in GM vehicles after 2006. CAN offers significantly higher bandwidth, allowing for faster data transfer and more complex communication between various electronic control units (ECUs).
OBD-II Compatibility in Chevrolet Vehicles (Partial List)
| Model | Engine | Year (starting from) | OBD-2 Protocol |
|---|---|---|---|
| Chevrolet Camaro | 6.2 V8, Gasoline (405HP) | 2012 | CAN 11bit (500kb) |
| Chevrolet Captiva | 2.2 VCDI, Diesel (163HP) | 2011 | CAN 11bit (500kb) |
| Chevrolet Corvette | V8, Gasoline (400HP) | 2007 | CAN 11bit (500kb) |
| Chevrolet Cruze | 2.0 VCDI, Diesel (163HP) | 2011 | CAN 11bit (500kb) |
This list demonstrates the increasing adoption of the CAN bus in later models.
Conclusion
Understanding the DLC 3 OBD2 pinout, especially the transition from J1850 to CAN, is fundamental for accurate vehicle diagnostics. While HDMI is not a standard interface for OBD2 data retrieval, this pinout information remains crucial for utilizing traditional diagnostic tools and understanding the underlying communication protocols within your vehicle. Always consult your vehicle’s specific service information for the most accurate and up-to-date pinout diagram.
