Test D: Flash Code 4 - Vehicle Speed Sensor (VSS) Circuit
- Check Speedometer Operation - Test drive vehicle and observe speedometer operation. If speedometer operates properly, go to next step. If speedometer does not operate properly, see INSTRUMENT PANEL article to continue diagnosis.
- Check Gray/Black Wire For Open - On Taurus SHO, disconnect ABS control module connector C1057 (located behind left headlight). Using an ohmmeter, check resistance in Gray/Black wire between speed control servo/actuator connector C102 terminal No. 3 and ABS control module connector C1057. On all other models, disconnect vehicle speed sensor connector C1043 (located near upper center of transaxle). Using an ohmmeter, check resistance in Gray/Black wire between speed control servo/actuator connector C102 terminal No. 3 and vehicle speed sensor connector C1043. On all models, if resistance is less than 5 ohms, replace speed control servo/actuator and perform self-test diagnostics. If resistance is 5 ohms or more, repair open in Gray/Black wire and perform SELF-DIAGNOSTIC TEST under SELF-DIAGNOSTIC SYSTEM.