ABS Wheel Speed Sensor
2021 Honda Accord · 1.5L I4 Turbo
Sensor Type
hall-effect
Waveform Type
dc-square
Location
One sensor per wheel: front sensors mounted in steering knuckle adjacent to CV axle tone ring; rear sensors mounted in trailing arm/knuckle area near wheel bearing tone ring
Pins
2-pin connector
Timebase
10ms/div at 5 mph, 2ms/div at 30+ mph
Voltage Scale
2V/div
Trigger
2.5V, rising edge
Wiring
Front Left: Black/Yellow (signal), Black (ground); Front Right: Blue/Orange (signal), Black (ground); Rear Left: Green/Red (signal), Black (ground); Rear Right: White/Blue (signal), Black (ground)
Expected Voltage Range
At Idle
0V to 5V
At Higher RPM
0V to 5V
Expected Pattern
Digital square wave alternating between 0V and 5V, frequency proportional to wheel speed, 48-tooth tone ring generates 48 pulses per revolution
Known-Good Waveform
Clean square wave transitions between 0V and 5V with sharp rising and falling edges. At 5 mph expect approximately 6-8 Hz, at 30 mph expect 40-50 Hz. All four sensors should show identical frequency when driving straight at constant speed. Duty cycle should remain near 50% across all speeds.
Common Failure Patterns
No signal output, voltage remains at 0V or 5V constantly
Cause: Failed Hall effect sensor IC, broken wiring, or loss of power/ground to sensor
Intermittent signal dropouts, missing pulses in waveform
Cause: Damaged tone ring teeth, excessive bearing play causing air gap variation, corroded sensor connector
Diagnostic Tips
Honda uses active Hall-effect sensors requiring 12V power supply - verify voltage at connector. Common issue is water intrusion at front sensor connectors causing corrosion. Compare all four sensor frequencies simultaneously while driving to identify faulty sensor; variance greater than 2-3 Hz indicates problem.
Related Diagnostic Trouble Codes
C0035C0040C0045C0050
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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