C2406

Code

Generic C — Chassis

Right Rear Wheel Speed Sensor Signal — Intermittent

Brand: Generic

Type: C — Chassis

Views: UK: 10 EN: 15 RU: 10

AI status

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Page language: EN

Causes

Damaged or contaminated right rear wheel speed sensor
Broken, chafed or corroded wiring or connector at the sensor
Intermittent connector contact (water intrusion, corrosion, loose pin)
Damaged or missing tone/ring wheel (reluctor) on hub/rotor
Excessive air gap between sensor and tone ring
Faulty wheel bearing causing sensor misalignment

Symptoms

ABS and/or traction/stability warning lamp illuminated intermittently
Intermittent or inconsistent ABS operation during braking
Traction control may engage unexpectedly or fail to engage
Possible speedometer fluctuations (on some vehicles)
Occasional loss of wheel speed reading for right rear on scan tool/live data

What to check

Retrieve freeze frame and live data with a scan tool; note behavior of right rear wheel speed while stationary and during wheel rotation
Perform a visual inspection of sensor, connector, and wiring harness at the right rear hub and along routing to chassis
Wiggle the wiring harness and connector while watching live data or DTC status to reproduce the fault
Measure sensor resistance and continuity to the module/connector pins (compare to vehicle spec)
Check for corrosion, bent pins, water ingress, or poor mating at the connector
Inspect tone ring for cracks, missing teeth, heavy rust, or debris; check air gap and alignment

Signal parameters

Passive (variable‑reluctance) sensor: DC resistance typically in the hundreds to low thousands of ohms (vehicle spec varies); generates an AC voltage proportional to wheel speed (low-speed VAC often >0.1–1.0 VAC and increases with RPM).
Active (Hall/electronic) sensor: typically has a supply/reference (often ~5 V) and produces a digital square wave or pulsed voltage (0–5 V or 0–12 V depending on system). Frequency increases with wheel speed.
Expected waveform: clean, consistent pulses with amplitude and frequency proportional to wheel rotation; gaps, missing pulses or noisy waveform indicate a problem.
Typical air gap: small and vehicle‑specific (often ~0.5–2.0 mm); excessive gap reduces signal amplitude and can cause intermittent readings.

Diagnostic algorithm

Connect a capable scan tool, read C2406 and any related codes; note freeze frame and live wheel speed values.
Attempt to reproduce fault: with vehicle safely raised, rotate right rear wheel by hand (or drive at low speed) while monitoring right rear wheel speed on the scanner; wiggle sensor harness/connectors to check for intermittent behavior.
Visually inspect sensor, mounting, tone ring, and harness. Look for physical damage, contamination, missing tone teeth, or excessive rust/debris.
Unplug sensor connector, inspect pins for corrosion/looseness, and clean or repair connector as needed. Reconnect and test again.
Measure sensor resistance (for passive) or supply/reference and output (for active) at the connector; compare to service specifications. Check continuity from sensor connector to ABS module pins.
Use an oscilloscope or lab scope to verify waveform while wheel is rotated. Look for consistent pulse amplitude and shape; intermittent dropouts indicate sensor/harness/connector problem.
Check and correct air gap between sensor and tone ring per vehicle spec; replace sensor or tone ring if damaged or gap cannot be corrected.
Repair damaged wiring (splice, butt connectors, or replace harness) and replace sensor or tone ring as required. Secure harness away from heat/moving parts to prevent recurrence.
Clear codes, perform a test drive and re-scan to ensure the code does not return and that wheel speed data is steady.
If intermittent problem persists after sensor/harness/tone ring service, inspect ABS module connector and grounds; consider module testing or replacement as last resort.

Likely causes

Wiring or connector damage (most common for intermittent faults)
Contaminated or failing wheel speed sensor
Damaged or misaligned tone ring / excessive air gap
Intermittent ground or power supply to active sensor

Fault status

⚠️ Status

Right rear wheel speed sensor signal intermittent — irregular or missing pulses detected from the right rear wheel speed sensor circuit. May illuminate ABS/traction lights and affect stability control.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5 - 2.0 hours

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