Four sensors total, one at each wheel hub assembly mounted to the steering knuckle (front) or axle housing (rear), reading tone rings pressed onto axle shafts
Pins
2-pin connector
0
Timebase
10ms/div at 30 mph, 2ms/div at highway speeds
Voltage Scale
2V/div
Trigger
2.5V, rising edge
Wiring
Front: White/Light Blue and Black/Light Green; Rear: Light Green/White and Tan/Orange (varies by wheel position)
Expected Voltage Range
At Idle
0V to 0V
At Higher RPM
0.3V to 5V
Expected Pattern
Digital square wave signal alternating between approximately 0.3V (low) and 5.0V (high) with 50% duty cycle. At 30 mph, frequency is approximately 65-75 Hz per wheel. Pattern shows clean transitions with consistent tooth spacing from 48-tooth tone ring
Known-Good Waveform
Clean digital square wave with sharp rise and fall times (less than 1ms transition). At constant vehicle speed, frequency should be consistent with uniform spacing between pulses representing each tone ring tooth. All four wheel speed sensors should show matching frequencies when driving straight; front wheels may differ slightly from rears due to tire diameter differences or 4WD operation.
Common Failure Patterns
No signal or flat line at 0V while wheel is rotating
Cause: Failed hall-effect sensor, broken wiring, or loss of power/ground to sensor
F-150 4WD models are prone to front wheel bearing wear causing excessive sensor airgap. Compare all four wheel speed sensor frequencies at the same vehicle speed to identify outliers. Check for metal debris buildup on magnetic sensor tip and verify tone ring has no missing or damaged teeth by rotating wheel slowly while monitoring pulse count.
Related Diagnostic Trouble Codes
C0035C0040C0045C0050
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.