Initial Inspection and Diagnostic Overview

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS
1. If either Electronic Brake Control Module (EBCM) or Sensing and Diagnostic Module (SDM) are not accessible with a scan tool, check for an open in PPL/WHT wire between component and DLC-OBD II terminal 9.
2. If the Engine Control Module (ECM) is not accessible with a scan tool, check for an open in PPL/GRN wire between ECM and DLC-OBD II terminal 7.
3. Check for loose or damaged terminals at DLC-OBD II.
4. Before component replacement, check for poor connections at related component and in-line harness connector terminal connections.
^ Check for an open (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in an continuity voltage check with the 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 "Troubleshooting Procedures,"). Diagnostic Aids
^ Refer to System Diagnosis. System Diagnosis