For 1990-2009 cars only
- Inspect for the proper connection of the scan tool to the data link connector (DLC).
- Inspect for loose or missing terminals at the DLC.
- If the vehicle control module (VCM)/powertrain control module (PCM) is not accessible with a scan tool, inspect for an open in CKT 1049 (DK GRN) between the component and splice pack 205 (SP205).
- If the electronic brake control module (EBCM) is not accessible with a scan tool, inspect for an open in CKT 1122 (LT BLU) between the component and splice pack 205 (SP205).
- If the body control module (BCM) is not accessible with a scan tool, inspect for an open in CKT 1037 (LT GRN) between the component and splice pack 205 (SP205).
- If the instrument cluster is not accessible with a scan tool, inspect for an open in CKT 1036 (GRY) between the component and splice pack 205 (SP205).
- If the automatic transfer case (ATC) control module is not accessible with a scan tool, inspect for an open in CKT 1133 (DK GRN/WHT) between the component and splice pack 205 (SP205).
- If the scan tool will not communicate with any module on the class 2 data line, inspect for an open in CKT 1132 (PPL) between splice pack 205 (SP205) and DLC terminal 2.
- If the Inflatable restraint sensing diagnostic module is not accessible with a scan tool, inspect for an open in CKT 800 (TAN) between the component and the DLC terminal 9.
- Inspect for the proper installation of the aftermarket electronic equipment that may affect the integrity of the other systems.
- Inspect for a broken, or partially broken, wire inside of the insulation. A broken, or partially broken, wire could cause the system to malfunction but prove good in a continuity/voltage test with the system disconnected. The circuits may be intermittent or resistive when loaded. If possible, inspect the circuits by monitoring for a voltage drop with the system operation (under load).
