Initial Inspection and Diagnostic Overview

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS
1. Check all CKT 800 (TAN) and CKT 1807 (PPL) wiring for an open or short to ground.
2. Check all CKT 835 (DK GRN) wiring for an open or short to ground.
3. Check all serial data line component connectors for proper terminal contact, beginning with suspect component.
4. Check all serial data line component ground wiring for high resistance (caused by poor terminal contact, frayed wires, etc.).
5. Check all serial data line components, beginning with suspect component.
6. Before component replacement, check for poor terminal contact at component connectors and in-line harness connectors; refer to Troubleshooting Procedures.
7. Check for a broken (or partially broken) wire inside of the insulation which could cause system failure but prove GOOD in a continuity/voltage check. (Refer to Troubleshooting Procedures.)
8. Check for proper installation of aftermarket electronic equipment which may effect the integrity of other systems. (Refer to Troubleshooting Procedures.) Diagnostic Aids