Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
ISO 26021-3: Road Vehicles — End-of-Life Activation — Part 3: Data Link Connector
Physical Connector Specifications for External Pyrotechnic Activation Tools
1. Connector Physical Specifications and Pin Assignments
ISO 26021-3 specifies the data link connector (DLC) that provides the physical interface between the end-of-life activation tool and the vehicle’s pyrotechnic control system. The connector is based on the SAE J1962 / ISO 15031-3 16-pin DLC form factor already present in all light-duty vehicles for emissions-related diagnostic access. However, ISO 26021-3 extends the pin assignment to include dedicated pyrotechnic activation signals beyond the standard OBD-II pinout.
The ISO 26021-3 DLC is physically identical to the standard OBD-II connector (SAE J1962 Type A), ensuring backward compatibility and eliminating the need for a separate connector. The distinction is in the pin usage: certain pins that are reserved or manufacturer-discretionary in the standard OBD-II pinout are assigned specific pyrotechnic activation functions under ISO 26021-3.
The connector is a 16-pin female (vehicle side) trapezoidal D-sub style connector with a latching mechanism that prevents accidental disconnection during operation. Pin 4 (chassis ground) and pin 5 (signal ground) serve dual purposes — providing ground return for both standard diagnostics and the pyrotechnic activation circuit. Pin 16 provides battery positive voltage. The newly assigned pins for pyrotechnic activation include a dedicated activation bus line and a pyrotechnic system enable signal that must be asserted before any activation command can be executed.
| Pin | Standard OBD-II Signal | ISO 26021-3 Pyrotechnic Function |
|---|---|---|
| 1 | Manufacturer discretionary | Pyrotechnic activation bus (PAB) — dedicated CAN bus for deployment commands |
| 4 | Chassis ground | Ground return for activation circuit (shared) |
| 5 | Signal ground | Signal ground for activation bus (shared) |
| 6 | CAN-H (ISO 15765-4) | CAN-H for pyrotechnic bus (shared or separate per vehicle implementation) |
| 9 | Manufacturer discretionary | Pyrotechnic system enable (PSE) — 12 V enable signal for activation circuit power |
| 14 | CAN-L (ISO 15765-4) | CAN-L for pyrotechnic bus (shared or separate) |
| 16 | Battery positive (+12 V / +24 V) | Power supply for activation tool (limited to 5 A by the standard) |
Pin 9 (Pyrotechnic System Enable) is a critical safety feature. This pin must be driven to battery voltage by the activation tool to enable the vehicle’s pyrotechnic control unit’s firing circuit power supply. If this signal is absent, the pyrotechnic control unit remains in a safe, non-activatable state regardless of any messages received on the communication bus. This provides a hardware-level interlock independent of software security.
2. Electrical Characteristics and Durability Requirements
The electrical specifications for the ISO 26021-3 DLC are designed to withstand the harsh environment of automotive end-of-life processing, which may involve exposure to moisture, dust, vibration, and extreme temperatures. The connector contacts must be rated for a minimum of 10,000 mating cycles — significantly higher than the 500-cycle rating of standard OBD-II connectors — reflecting the high-usage environment of scrapyard and dismantling facility operations.
The activation bus pins (pin 1 for PAB and pins 6/14 for CAN) must support the CAN transceiver electrical characteristics per ISO 11898-2 including differential voltage levels of 1.5 V to 3.5 V (dominant) and 0.5 V to 2.5 V (recessive), with a minimum baud rate of 250 kbit/s and recommended rate of 500 kbit/s for the pyrotechnic activation bus. The PSE pin (pin 9) must be capable of carrying 2 A continuous current with a voltage drop not exceeding 0.5 V at rated current, and must incorporate overcurrent protection at 3 A minimum.
The connector is designed with a coding/keying feature to prevent incorrect insertion of activation tools into non-pyrotechnic vehicles or vice versa. The activation tool connector may include a mechanical key that corresponds to a matching recess in the vehicle-side DLC, ensuring that only authorized tools can access the pyrotechnic activation functions. This physical keying complements the software-level security defined in ISO 26021-2.
3. Connector Location and Vehicle Integration Engineering
ISO 26021-3 specifies that the pyrotechnic activation DLC should be located in a position accessible without requiring vehicle disassembly, and clearly marked with a standardized symbol (a stylized airbag icon with a recycling arrow, specified in ISO 26021-3 Annex A). The standard recommends, but does not mandate, that the DLC be co-located with the standard OBD-II connector (typically within 600 mm of the steering wheel, per ISO 15031-3). If a separate connector is used for pyrotechnic activation, it must be within 300 mm of the OBD-II connector and distinctively colored — orange with a black surround is the recommended color scheme.
From a vehicle integration perspective, the wiring from the DLC to the pyrotechnic control unit must be physically protected against abrasion and heat, must not share conduit or routing with high-voltage cables (in electric and hybrid vehicles), and must be colored orange or have orange markings to indicate its association with the pyrotechnic safety system. The ground path for the activation circuit must be independent of the vehicle body ground to ensure reliable operation even when the vehicle’s grounding system is degraded by corrosion — a common condition in end-of-life vehicles.
Never apply external voltage to any DLC pin without first verifying the pin assignment for the specific vehicle. Incorrect connection can bypass safety interlocks and cause unintended pyrotechnic device activation. Always use an ISO 26021-3 compliant breakout box or adapter that provides visual indication of signal presence and polarity before connecting the activation tool.
FAQs
Q1: Is the ISO 26021-3 connector compatible with all vehicle makes and models?
The standard is designed for universal compatibility, but implementation is voluntary. Most major vehicle manufacturers have adopted ISO 26021-3 pin assignments for new models since 2015. Older vehicles may use manufacturer-specific connectors or require adapter cables.
The standard is designed for universal compatibility, but implementation is voluntary. Most major vehicle manufacturers have adopted ISO 26021-3 pin assignments for new models since 2015. Older vehicles may use manufacturer-specific connectors or require adapter cables.
Q2: Can the standard OBD-II scanner damage the pyrotechnic activation circuit?
No. The pyrotechnic activation bus is electrically isolated from the standard diagnostic bus in the vehicle’s wiring. A standard OBD-II scanner that does not drive the PSE pin (pin 9) will not interact with the pyrotechnic control system in any way. Conversely, an ISO 26021-3 activation tool will not interfere with standard diagnostic functions when connected to a non-pyrotechnic vehicle — the activation commands will simply be ignored at the application layer.
No. The pyrotechnic activation bus is electrically isolated from the standard diagnostic bus in the vehicle’s wiring. A standard OBD-II scanner that does not drive the PSE pin (pin 9) will not interact with the pyrotechnic control system in any way. Conversely, an ISO 26021-3 activation tool will not interfere with standard diagnostic functions when connected to a non-pyrotechnic vehicle — the activation commands will simply be ignored at the application layer.
Q3: What is the maximum cable length between the activation tool and the vehicle DLC?
For reliable CAN communication at 500 kbit/s, the total cable length (tool cable plus vehicle wiring) should not exceed 5 meters. Longer cables introduce signal reflection and attenuation that can cause communication errors. If longer reach is required, a CAN repeater or extended-length certified cable must be used.
For reliable CAN communication at 500 kbit/s, the total cable length (tool cable plus vehicle wiring) should not exceed 5 meters. Longer cables introduce signal reflection and attenuation that can cause communication errors. If longer reach is required, a CAN repeater or extended-length certified cable must be used.
Q4: How are connector pins protected against short circuits?
Each pin in the activation circuit must be individually current-limited. The PAB and CAN bus pins use the transceiver’s inherent short-circuit protection (typically ±40 V tolerant and thermally protected). The PSE pin requires an external resettable fuse or electronic current limiter set to 3 A trip threshold.
Each pin in the activation circuit must be individually current-limited. The PAB and CAN bus pins use the transceiver’s inherent short-circuit protection (typically ±40 V tolerant and thermally protected). The PSE pin requires an external resettable fuse or electronic current limiter set to 3 A trip threshold.
