C0311

Code

Generic C — Chassis

Right Front Wheel Speed Sensor Circuit Range/Performance

Brand: Generic

Type: C — Chassis

Views: UK: 8 EN: 13 RU: 11

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Faulty right-front wheel speed sensor (damaged or internally open/shorted)
Damaged, corroded or loose connector at the sensor or at the ABS module
Broken, bent or contaminated tone/reluctor ring (missing teeth, heavy rust/debris)
Incorrect air gap between sensor and tone ring
Wiring harness damage (open, short to ground or short to power)
Faulty ABS/ESC module or sensor input circuit

Read and record freeze-frame and live data with a scan tool (wheel speed values and comparison between corners)
Visually inspect right-front sensor, connector and wiring for damage, corrosion or contamination
Inspect tone/reluctor ring on the hub/axle for missing teeth, heavy rust or debris
Check sensor air gap and mounting security
Measure sensor resistance (for passive sensors) and reference voltage (for active sensors) — consult vehicle spec
Perform an oscilloscope or scan-tool waveform check while spinning the wheel to confirm signal amplitude and shape

Passive (two‑wire) sensors: DC resistance varies by make—commonly in the low hundreds to a few kiloohms; produce AC voltage whose amplitude increases with speed (very small at very low speeds, up to ~1 V RMS+ at higher speeds). Values are vehicle-specific.
Active (three‑wire) sensors: have a reference supply (typically ~5 V) and ground plus a varying signal (square or sinusoidal) with amplitude within 0–5 V depending on design.
Expected waveform: regular pulses with frequency proportional to wheel speed; amplitude and shape depend on sensor type and speed.
Typical air gap: small clearance (often

Verify and record DTCs and freeze-frame data with a scan tool; note if multiple wheel speed DTCs are present.
Visually inspect sensor, connector, wiring route, and tone ring for physical damage, contamination or corrosion; repair obvious issues.
With connector disconnected, measure sensor resistance (passive) or check reference supply and signal wiring (active) against vehicle spec.
Reconnect and monitor live wheel speed data while slowly rotating the wheel (use scan tool or oscilloscope). Look for missing pulses, low amplitude or noise.
Wiggle the harness/connectors while observing live data to detect intermittent opens/shorts.
Inspect tone/reluctor ring: look for missing/bent teeth, heavy rust, metal debris, or warped ring; correct as needed.
Check and measure sensor air gap and mounting alignment; adjust or replace mount if required.
If electrical tests on sensor/wiring are good but signal is still incorrect, swap the sensor with another corner (if identical) to see if the fault follows sensor or stays with hub.
If the fault remains on vehicle after sensor/wiring checks and swap, suspect ABS module input or grounding/power issues; verify module power, ground and CAN communications.
After repairs, clear codes, re-test (road or wheel spin) and confirm proper operation. If intermittent, perform extended road test to ensure reliability.