ABS Wheel Speed Sensor
2021 Toyota RAV4 · 2.5L I4
Sensor Type
variable-reluctance
Waveform Type
ac-sine
Location
Four sensors: one at each wheel hub, mounted to steering knuckle (front) and rear axle carrier (rear), sensing reluctor ring on wheel bearing
Pins
2-pin connector
Timebase
10ms/div at 25mph, 5ms/div at 50mph
Voltage Scale
500mV/div to 1V/div
Trigger
0V, rising edge
Wiring
Front Left: White/Black and White wires. Front Right: White/Red and White wires. Rear Left: White/Blue and White wires. Rear Right: White/Green and White wires
Expected Voltage Range
At Idle
0V to 0V
At Higher RPM
-2.5V to 2.5V
Expected Pattern
AC sine wave with 48 pulses per revolution, amplitude increases with wheel speed, symmetrical positive and negative peaks
Known-Good Waveform
At 25mph, expect clean sine waves with 1.2-2.0V peak-to-peak amplitude, frequency approximately 85-95Hz. All four sensors should show similar amplitude and frequency when vehicle traveling straight. Waveform should be symmetrical with smooth transitions between peaks, minimal noise or distortion, and consistent amplitude across all teeth.
Common Failure Patterns
Amplitude drops below 0.5V peak-to-peak or erratic missing pulses
Cause: Excessive air gap between sensor tip and reluctor ring due to bearing wear or sensor backing out
No signal or flat line, 0V DC
Cause: Open circuit in sensor coil, broken wire in harness, corroded connector pins
Irregular amplitude peaks, some teeth showing lower voltage
Cause: Damaged reluctor ring teeth, rust or debris buildup on tone ring, cracked wheel bearing
Diagnostic Tips
RAV4 uses 48-tooth reluctor rings integrated into sealed wheel bearings. Compare all four sensor outputs simultaneously during road test; mismatched amplitudes indicate bearing wear or sensor issues. Air gap spec is non-adjustable; low amplitude requires bearing or sensor replacement. Check sensor resistance: should be 800-1400 ohms.
Related Diagnostic Trouble Codes
C0035C0040C0045C0050
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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