00290 Rear Left ABS Wheel Speed Sensor G46: Fault Diagnosis
Fault code 00290 is stored by the ABS control module on Volkswagen Group vehicles when the signal from the rear left wheel speed sensor, labelled G46 in wiring diagrams, does not match what the module expects. It usually turns on the ABS and stability control warnings, and those systems switch off while ordinary braking remains. This guide explains how to record the symptoms, separate the likely causes, check them in a sensible order and decide how urgently the car needs attention.
Establish the symptoms
Start by noting exactly when the warning appears. A fault present immediately after start-up points to an electrical break or a missing sensor signal. A light that comes on only above a certain speed, over bumps, in wet weather or after a hard turn suggests an intermittent connection, a contaminated reader ring or wheel bearing play. Write down the full fault text from the scan tool, because the suffix matters: open or short to ground, no signal, implausible signal and mechanical malfunction each lead to different checks. Also note whether the code is static or sporadic, any freeze frame data and the fault frequency counter.
Record associated signs too. A humming or grinding noise from the rear left wheel, ABS activating at low speed on a dry road, a pulsing pedal during gentle stops, or features that rely on wheel speed, such as stability control or hill hold, being disabled all add evidence. Finally, list recent work. New rear brake pads, brake rotors or a caliper, a replaced wheel bearing or hub, suspension work, a kerb strike or pressure washing underneath are common triggers, because the sensor and its harness sit right beside those parts and are easy to disturb.
Distinguish plausible causes
The sensor itself is a frequent culprit, but it is not the only one. Wiring damage is common on the rear axle because the harness flexes with suspension travel. A chafed cable or a corroded connector usually produces open-circuit or short-circuit faults, and an intermittent break may show as a sporadic code that returns when the suspension moves. If an electrical fault appears or clears when the harness is moved, the wiring becomes a stronger suspect than the sensor.
When the left rear sensor reports a mechanical malfunction, the module usually sees a signal, but one that is irregular or out of step with the other wheels. That points towards the part the sensor reads rather than its circuit: a reader ring, either a toothed ring or a magnetic encoder depending on design, that is cracked, corroded or packed with rust and brake dust, or a wheel bearing with play that changes the air gap. A sensor that is not fully seated, or is pushed out by rust under its mounting, has the same effect. Less common causes include a mismatched tire size, a replacement hub or bearing that is wrong for the vehicle fitment and, rarely, a fault inside the ABS module. A module fault becomes less likely when only one wheel is affected and the other three read normally.
Checks in a useful order
Begin with checks any owner can safely make. Read and save the fault memory, clear it, and see whether it returns immediately, after a short drive or only occasionally. With the car parked on level ground, look behind the rear left wheel for a damaged, unclipped or stretched sensor lead, a loose connector, or debris and rust around the sensor. Confirm that all four tires are the same size and similarly worn and inflated. Note the condition of the brake pads, the rotors and the brake fluid level while you are there, since a separate brake problem changes the urgency, but do not assume it is connected to the code.
The next steps need tools, vehicle-specific information or a qualified technician. Viewing live wheel speeds on a scan tool while driving slowly in a straight line is the most useful test: the rear left value should track the other wheels closely without dropping out or jumping. Checking the bearing for play requires the car to be safely supported on stands, and removing the sensor or hub to inspect the reader ring needs the correct procedure and torque values. Electrical testing of the circuit between sensor and module should follow the wiring diagram for that model. Many current sensors are active types that cannot be judged with a simple resistance reading, so the test method must match the sensor design.
Interpret the findings
A code that returns at once with an open or short description, together with live data showing zero speed from the rear left wheel, establishes a circuit or sensor fault, but not which one. Continuity and short-circuit checks of the harness, or swapping with the right side sensor where the parts are interchangeable on that model, narrow it down. A signal that is present but erratic, especially at a particular speed or under load, supports a reader ring, air gap or bearing problem, which should be confirmed by inspection before a sensor is ordered.
Bearing play, a damaged encoder or rust lifting the sensor all mean a new sensor alone will not cure the fault, and the code is likely to return. Conversely, a clean, correctly seated sensor with sound wiring and a smooth live signal that still logs faults may justify replacing the sensor or investigating the module further. After any repair, clear the memory, drive a route that previously triggered the fault and recheck live data rather than relying on the warning light alone, since some faults need several drive cycles to reappear.
Urgency and next action
With only the ABS and stability warnings lit, the normal hydraulic brakes still work, but the wheels can lock under hard braking and stability control may not intervene, so drive gently, leave extra distance and arrange diagnosis soon. Stop driving and have the car inspected if the red brake warning light comes on together with the ABS light, if the pedal feels soft or travels further than usual, if the brake fluid level is low, or if there is grinding, heat or wobble from the rear left wheel. On many vehicles the combined warning means electronic brake force distribution is also disabled, which can let the rear wheels lock earlier. A failing bearing is a safety issue in its own right. There is no reliable way to say how far the car can safely travel with this fault.
Give the workshop the full fault text with its status and frequency, the freeze frame data, when the warning appears, any noises, and details of recent brake, bearing or suspension work. Have the vehicle identification number available so the correct sensor, bearing or hub can be matched to the vehicle fitment, and ask for bearing play, friction material thickness and other wear limits to be checked against the manufacturer's specifications.