C0050
Right Rear Wheel Speed Circuit MalfunctionC0050 is a generic OBD-II chassis diagnostic trouble code: Right Rear Wheel Speed Circuit Malfunction. It is logged by the engine control unit when the chassis monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What C0050 means
DTC C0050 is stored when the ABS/ESC control module detects an electrical fault in the right rear wheel speed sensor circuit. The code logic is symmetric with C0045: an open, short, or erratic/absent signal from the right rear sensor causes the EBCM to disable ABS, traction control, and electronic stability control for the current ignition cycle and illuminate the ABS warning lamp.
The right rear sensor faces the same environmental hazards as the left rear — heat from the brake caliper, water ingress, road debris, and harness flexing through the full range of suspension travel. On GM full-size trucks and SUVs, GM Technical Service Bulletin PIC5428G documents a pattern failure where metallic debris accumulates on the hub's magnetic encoder ring; in those cases cleaning the ring and sensor tip often resolves the code without parts replacement. When the hub bearing itself is worn and has internal play, the variable air gap it creates can produce an intermittent signal that sets the code only under load or at certain speeds.
Because all four wheel speed signals are cross-referenced by the stability control algorithm, even a single bad sensor can cause the ESC system to make incorrect corrections or refuse to operate at all. Vehicles with active rear differentials or electronically controlled rear axles may also exhibit degraded performance. Normal foundation braking remains available, but the vehicle should be treated as safety-compromised until the circuit fault is resolved.
Common causes
Most-frequently reported root causes when C0050 is logged.
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1
Failed right rear wheel speed sensor with internal open circuit or short.
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2
Corroded, water-intruded, or physically damaged sensor pigtail connector.
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3
Chafed or broken wiring harness routing past rear suspension or exhaust components.
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4
Metallic debris accumulation on the magnetic encoder ring causing erratic signal output.
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5
Cracked, missing-tooth, or heavily rusted hub encoder ring.
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6
Worn rear hub bearing creating excessive air gap between sensor tip and encoder ring.
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7
EBCM input channel failure or poor EBCM power/ground connection (less common).
Symptoms drivers notice
How to diagnose C0050
A typical diagnostic flow when this code is present.
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1
Connect a scan tool to the ABS module, retrieve all stored codes, and check freeze-frame vehicle speed and wheel speed data.
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2
View live wheel speed readings at low speed; the right rear sensor should track the other three wheels within a few km/h.
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3
Inspect the sensor body, mounting surface, and pigtail connector for physical damage, corrosion, and proper seating.
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4
Examine the encoder ring on the hub bearing for metallic debris, rust jacking, cracks, or missing segments; clean or replace as needed.
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5
Check the hub bearing for play by rocking the wheel with the vehicle safely raised; replace a worn bearing with an integrated encoder ring.
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6
For active sensors, verify 5 V reference and ground at the connector with the ignition on; for passive sensors, measure resistance and scope the AC waveform while spinning the wheel.
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7
Repair or replace the faulty component, clear codes, and verify with a road test that the right rear sensor matches the other channels in live data.
Related chassis codes
- C0000 — Vehicle Speed Information Circuit Malfunction
- C0035 — Left Front Wheel Speed Circuit Malfunction
- C0040 — Right Front Wheel Speed Circuit Malfunction
- C0041 — Right Front Wheel Speed Sensor Circuit Range/Performance (EBCM)
- C0045 — Left Rear Wheel Speed Circuit Malfunction
- C0046 — Left Rear Wheel Speed Sensor Circuit Range/Performance (EBCM)
Frequently asked questions
Can C0050 cause issues with my rear differential or AWD system?
Yes. Vehicles with torque-vectoring rear differentials, electronic limited-slip, or AWD torque management rely on accurate wheel speed data. A bad right rear sensor can cause the AWD/electronic differential controller to disengage or act erratically, in addition to disabling ABS and ESC.
GM TSB PIC5428G is mentioned for C0050 — what does it cover?
That TSB addresses metallic debris accumulating on the hub's passive magnetic encoder ring, causing weak or intermittent sensor signals. The fix is to clean the encoder ring surface and sensor tip with a clean cloth, reinstall, and retest. If the ring is damaged or the code returns, hub assembly replacement is required.
Why does C0050 only appear after rain or car washes?
Water intrusion into a partially corroded connector or a micro-crack in the sensor body can cause intermittent shorts that disappear once dry. Inspect the connector boot seal, apply dielectric grease to the connector pins, and investigate the sensor pigtail for hairline insulation cracks.
Does C0050 require replacing the whole hub assembly or just the sensor?
On many modern vehicles the encoder ring is press-fit into the hub bearing and cannot be replaced separately; if the ring is damaged, the hub must be replaced as an assembly. If only the sensor is faulty and the ring is intact, replacing just the sensor is sufficient.
Disabling C0050 in software
RaceTune can permanently disable C0050 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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