Cutlass V6-191 3.1L VIN M SFI (1998)
Information Bus: Initial Inspection and Diagnostic Overview
1. Check scan tool operation on a known good vehicle to make sure tool is operating properly.
2. Check condition of IPC/HVAC BATT Fuse by visual inspection.
3. Verify that Grounds G102 and G201 are clean and tight.
4. Check for proper connection of scan tool to the Data Link Connector (DLC).
5. The following diagnostics assume that a communications failure is initially found during testing with the scan tool as per Driveability and
Emissions, Antilock Brakes, Supplemental Inflatable Restraints, Computer System Diagnosis.
6. If unable to communicate with the scan tool verify power and ground(s) for all component(s) on the Class 2 Serial Data Line.
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Check for a broken (or partially broken) wire inside the insulation which could cause system malfunction but prove GOOD in a continuity/voltage
check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring
for a voltage drop with the system operational (under load).
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Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (Refer to Troubleshooting
Procedures). See: Diagrams/Diagnostic Aids
