Scan Tool Does Not Communicate with UART Data Line. GMC Truck GMC Suburban

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC Suburban - 2WD 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Scan Tool Does Not Communicate with UART Data Line

Step	Action	Value(s)	Yes	No
1	Did you perform the SIR Diagnostic System Check?	--	Go to Step 2	SIR Diagnostic System Check
2	Turn the ignition switch to the RUN position. Connect a J 39200 Is the voltage less than the specified value?	4-5 volts	Go to Step 4	Go to Step 3
3	Is the voltage greater than the specified value?	4-5 volts	Go to Step 6	SIR Diagnostic System Check
4	Turn the ignition switch to the OFF position. Connect a J 39200 Is continuity present?	--	Go to Step 5	Go to Step 8
5	Locate and repair the short to ground in CKT 800 (TAN) between the Sensing and Diagnostic Module (SDM) and the DLC. Refer to SIR/SRS Wiring Repairs Is the repair complete?	--	SIR Diagnostic System Check	--
6	Disconnect the SDM connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement Turn the ignition switch to the RUN position. Connect a J 39200 Is the voltage greater than the specified value?	0 volts	Go to Step 8	Go to Step 7
7	Locate and repair the short to voltage in CKT 800 (TAN) between the Sensing and Diagnostic Module (SDM) and the DLC. Refer to SIR/SRS Wiring Repairs Is the repair complete?	--	SIR Diagnostic System Check	--
8	Perform the SDM Intergrity Check. Refer to Sensing and Diagnostic Module Integrity Check Did the SDM pass the check?	--	SIR Diagnostic System Check	Go to Step 9
9	Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement Is the repair complete?	--	SIR Diagnostic System Check	--