A brief description of the Suzuki Serial Data Link (Suzuki SDL)

The Serial Data Link is a diagnostic interface that allows fault codes and real time data to read from the ECU. This interface is very rarely referred to in documentation for early models but is sometimes shown on the schematic. There are two different connectors used, a 12-pin ALDL style connector and a 16-pin J1962 (OBD2) connector.

ALDL Connector

The ALDL connector is common on early models and has the SDL on pin M, Pins H and A provide 12V power and ground for a scan tool.

OBD2 (J1962) connector

The J1962 connector has the SDL on pin 9, this pin is reserved by the OBD2 specification for the manufacturers own use. Power for a scan tool is provided with 12V on pin 16 and ground on pin 5. If pin 7 is also populated then the main engine ECU will use the KWP2000 protocol rather than the SDL protocol.

The SDL is bi-directional one wire interface, there are few hand held scan tools available and these are intended for dealer use and cost thousands of dollars new. Vetronix (now Bosch) made the original Suzuki dealer tools, the Tech1 and the Tech 1A. Tech 1/1A cartridges can also be used in the Vetronix/Bosch Mastertech MTS3100 tool which also has a lot of extra functionality. The Tech 1A was replaced as the dealer tool by the Tech2, Suzuki cartridges for these are available through eBay but are most likely to be cloned, a prospective purchaser would need to check which models are supported. There was also a Carman tool available but information on this is limited. The latest dealer tool is the Denso manufactured SDT, however that tool has no support for Suzuki's SDL. To make the Serial Data Link available at an affordable cost I have produced a USB-SDL interface that can be used with a PC or laptop, please go to the for details. Interfaces designed for GM vehicles have been used with some success but the voltage levels are different and none are guaranteed to work.

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