Initial Inspection and Diagnostic Overview

1. CHECK for proper connections of Scan Tool to Data Link Connector (DLC).
2. CHECK for loose or missing Terminals at DLC.
3. If all Components are not accessible with a Scan Tool, CHECK for an open in BLK (750) or BLK (550) wire between Grounds G105 or G101/G103 and DLC Terminal 4 or 5 respectively.
4. If either VCM and/or BPMV are not accessible with a Scan Tool, then CHECK for an open in PPL (1807) wire between Module and DLC Connector.
5. If a single Component is not accessible with a scan tool, then CHECK for an open in PPL (1807) communication wire(s) between the affected component and DLC Connector.
^ CHECK for a broken (or partially broken) wire inside of 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).
^ CHECK for proper installation of aftermarket Electronic Equipment which may affect the integrity of other systems (See Diagnostic Aids for General Troubleshooting Procedures). Diagnostic Aids