Scan Tool Does Not Communicate With SDM

Circuit Description
The data link connector (DLC) is the provision for communicating with the Inflatable Restraint Sensing and Diagnostic Module (SDM). The DLC is located under the instrument panel. The DLC supplies B+ and ground to the scan tool. The scan tool communicates with the SDM and other Class 2 modules that are on the same data line through circuit 1807. The scan tool is connected to the DLC in order to perform the following functions:
^ Read the data list.
^ Read diagnostic trouble codes (DTCs).
^ Clear DTCs.

When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616-A Connector Test Adapter Kit. When a check for proper connection is requested, refer to General Electrical Diagnosis Procedures. When a wire, connector or terminal repair is requested, use J 38125-B Terminal Repair Kit and refer to Wiring Repair. Related Tests and Procedures

Test Description
2. This step checks to see if the scan tool operates properly.
4. This step checks for a proper connection at the data link connector (DLC).
6. This step checks for a proper connection at terminal A4 of the SDM wiring harness connector.
11. This step checks to see if there is an open or a high resistance in circuit 800.
13. This step checks to see if there is a short to ground in circuit 800.
15. This step determines if there is a short to B+ in circuit 800 or if there is a malfunctioning SDM.