Scan Tool Does Not Communicate With SDM
NOTE:
A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.
- Remove the scan tool from the Data Link Connector (DLC). Disconnect the Sensing and Diagnostic Module (SDM) connector. Test for an open or short to ground in the power circuit(s) to the SDM. See 1998 SYSTEM WIRING DIAGRAMS CHEVROLET - CAVALIER or 1998 SYSTEM WIRING DIAGRAMS PONTIAC - SUNFIRE article. If there is no fault in the power or ground circuits, go to next step. If there is any fault, repair and perform data link communications system check. See DATA LINK COMMUNICATIONS SYSTEM CHECK .
- Test for an open in the ground circuit(s) to the SDM. See 1998 SYSTEM WIRING DIAGRAMS CHEVROLET - CAVALIER or 1998 SYSTEM WIRING DIAGRAMS PONTIAC - SUNFIRE article. If there is no fault in the ground circuits to the SDM, go to next step. If there is any fault, repair and perform data link communications system check. See DATA LINK COMMUNICATIONS SYSTEM CHECK .
- Test for an open, short to ground or short to battery between terminal No. 9 of the DLC and terminal No. 5 of the SDM with a DVOM. See Figure . If there is no fault in the circuit, go to next step. If there is any fault, repair and perform data link communications system check. See DATA LINK COMMUNICATIONS SYSTEM CHECK .
- Replace the SDM. See SENSING & DIAGNOSTIC MODULE (SDM) under REMOVAL & INSTALLATION in AIR BAG RESTRAINT SYSTEM article in RESTRAINTS. Perform data link communications system check. See DATA LINK COMMUNICATIONS SYSTEM CHECK .