Scan Tool Does Not Communicate With SDM

Diagnostic Chart:

Diagram:

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 battery power and ground to the scan tool. The scan tool communicates with the SDM over the serial data circuit (CKT 800). The scan tool is connected to the DLC in order to perform the following functions:
- Reading the data list
- Reading Diagnostic Trouble Codes (DTCs)
- Clearing 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 Diagrams / Information & Instructions. When a wire, connector or terminal repair is requested, use J 38125-A Terminal Repair Kit and refer to Wiring Repair.

TEST DESCRIPTION
2. This test checks for proper operation of the scan tool.
4. This test checks for proper connection at the Data Link Connector (DLC).
6. This test checks for proper connection at the inflatable restraint Sensing and Diagnostic Module (SDM) harness connector.
11. This test checks for an open condition in CKT 800.
13. This test checks for a short-to-ground condition in CKT 800.
15. This test checks for a short-to-B+ condition in CKT 800.