Front Speed Sensor

1. Connect oscilloscope to speed sensor connector.
2. Run vehicle at 12.4 mph and inspect speed sensor output wave, Fig. 171

Fig. 171 Front & Rear Speed Sensor Inspection.:

3. Ensure "C" is at least 0.5 volts, Fig. 171. If it is not, replace speed sensor.
4. Ensure "B" is 30% more of "A". If it is not, replace driveshaft.