For 1990-2009 cars only
| • | Ensure all the mechanical components are operative before diagnosing the electrical portion of the selectable four-wheel drive (4WD) system. |
| • | In order to determine whether the vehicle is in two-wheel drive or four-wheel drive, lift the vehicle so that the wheels can spin freely. |
| • | Make sure that the 4WD fuse is not open. If open, locate and repair the source of the overload. Replace the fuse. |
| • | Inspect the inline connectors for corrosion |
| • | Inspect for a broken (or partially broken) wire inside of the insulation which could cause system failure 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 inspected by monitoring fuse voltage drop with the system operational (underload). |
| • | Inspect for the proper installation of aftermarket electronic equipment which may affect the integrity of other systems. Refer to Troubleshooting Procedures. |
| • | While performing diagnostic procedures, the ignition switch must be in RUN and the 4WD control lever must be in the 4WD ENGAGED position. |
