J1939 Connector Pinout Diagram – Male, Female, Black, Green

Hi, in this article, we are going to see the J1939 Connector Pinout Diagram. The J1939 connector is a standard communication interface used in heavy-duty vehicles such as trucks, buses, construction, and agricultural equipment to enable data transfer between electronic control units (ECUs). This communication protocol is based on the Controller Area Network (CAN) standard and it was developed by the Society of Automotive Engineers (SAE). The J1939 protocol defines both physical connector types and message formats which enables reliable communication for diagnostics, vehicle control, and data monitoring.

There are two types of J1939 connectors that are mostly used for practical applications. The black and green types of J1939 connectors refer to specific standardized connector types commonly used in off-highway and heavy-duty vehicle applications. It differentiates the network types or applications such as the Black J1939 Connector also known as Type I and the Green J1939 Connector also known as Type II. Both black and green connectors follow the J1939 pinout for CAN communication but they are physically separated by color for safety and compatibility reasons.

J1939 Connector Pinout Diagram(Male & Female) - Type I: Black

Here, you can see the pinout diagram of Type I or Black J1939 Connector for the both Male and Female.

The Black type J1939 Connector is used in 12V systems such as light-duty or medium-duty vehicles and smaller engines. This connector type has a 9-pin layout with CAN communication lines, ground, and power. The black color signifies to users or technicians that it’s intended for 12V J1939/CAN networks.

Pinout Explanation

Ground and Battery(Pins A and B): These pins provide the ground and positive power supply (typically 12V) to the connector that is used to power diagnostic tools.

J1939+ and J1939- (Pins C and D): These are the primary data lines for the J1939 CAN network which allows communication between vehicle ECUs (Electronic Control Units) at a data rate of 250 Kbps.

J1939 Shield (Pin E): This pin provides electromagnetic interference (EMI) shielding which helps maintain signal quality by minimizing noise from external sources.

J1708 (+) and J1708 (-) (Pins F and G): J1708 is a serial data bus standard (predecessor to J1939), often used in diagnostics for older heavy-duty vehicles. These pins allow backward compatibility for diagnostic tools to access information from J1708-based systems.

OEM Specific (Pins H and J): These pins are reserved for proprietary signals and are customizable based on specific manufacturer or equipment requirements, often used for custom diagnostics or auxiliary functions.

J1939 Connector Pinout Diagram(Male & Female) - Type II: Green

Here, you can see the pinout diagram of Type II or Green J1939 Connector for the both Male and Female.

The Green type J1939 Connector is generally designed for 24V systems such as heavy-duty vehicles and larger equipment. It also has the 9-pin layout but is specifically meant to handle higher voltage systems. The green color makes it easy to distinguish from the black 12V version, helping to avoid compatibility issues. The color coding helps technicians quickly identify the connector type to avoid cross-wiring 12V and 24V systems which can damage electronic components if connected incorrectly. 

Pinout Explanation

Ground and Battery(Pins A and B): These pins provide the ground and positive power supply (typically 24V) to the connector that is used to power diagnostic tools.

Pins C and D (J1939+ and J1939- 500 Kbps): These are the main CAN High and CAN Low lines for J1939, operating at 500 Kbps. This higher speed is suitable for faster data transfer and is commonly used in modern heavy-duty vehicles for real-time communication between critical systems.

J1939 Shield (Pin E): Same as the Black type here also, this pin provides electromagnetic interference (EMI) shielding which helps maintain signal quality by minimizing noise from external sources.

Pins F and G (J1708 / J1939 250 Kbps): These pins can either support J1708 (an older standard for serial data communication) or be configured as an additional J1939 connection at 250 Kbps. The dual compatibility allows manufacturers to use either protocol, depending on the application requirements or vehicle model.

Pins H and J (OEM Specific): Reserved for manufacturer-specific connections, these pins allow for proprietary data or additional functionality unique to a particular vehicle or equipment brand.

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