MG ZS

MG ZS (Gen2) Wheel Speed Sensor Fault

A Wheel Speed Sensor Fault indicates that the Anti-lock Braking System (ABS) Control Module has detected an abnormal or missing signal from one or more wheel speed sensors or their associated circuits. Each wheel speed sensor continuously monitors the rotational speed of its respective wheel and sends this information to the ABS module, which uses the data to control the Anti-lock Braking System (ABS), Electronic Stability Control (ESC), Traction Control System (TCS), Electronic Brakeforce Distribution (EBD), Hill Start Assist, and other advanced driver assistance functions. A faulty wheel speed sensor can disable these safety systems, illuminate multiple warning lights, and affect vehicle stability and braking performance. This fault applies to the MG ZS Gen2 (ZS11 platform), introduced from 2024 onwards.

Symptoms

  • ABS warning light illuminated
  • Electronic Stability Control (ESC) warning light illuminated
  • Traction Control System (TCS) warning light illuminated
  • Hill Start Assist warning (where equipped)
  • Check Engine Light may illuminate on some models
  • ABS no longer operates during hard braking
  • Reduced traction control performance
  • Stability control disabled
  • Speedometer or cruise control malfunction (depending on system design)
  • Multiple chassis system warning messages
  • Wheel speed sensor or ABS-related Diagnostic Trouble Codes (DTCs) stored

Possible Causes

  • Faulty wheel speed sensor
  • Damaged wheel speed sensor wiring
  • Open circuit in the sensor circuit
  • Short circuit to ground or battery voltage
  • Loose, damaged, or corroded electrical connectors
  • Damaged or contaminated magnetic encoder ring
  • Damaged reluctor ring or tone wheel
  • Excessive wheel bearing play
  • Incorrect wheel bearing installation affecting the encoder
  • Dirt, rust, or metallic debris interfering with sensor operation
  • Faulty ABS Control Module (rare)

Diagnosis

Diagnosis begins by confirming any stored Diagnostic Trouble Codes (DTCs) and reviewing freeze-frame and live wheel speed data using a compatible diagnostic scan tool. Live data should be monitored while driving to compare the speed readings from all four wheel speed sensors and identify any sensor producing an erratic, intermittent, or missing signal. The technician should inspect the affected wheel speed sensor, wiring harness, connectors, and mounting location for physical damage, corrosion, loose terminals, water intrusion, or broken wiring. The magnetic encoder ring or reluctor ring should be inspected for cracks, corrosion, contamination, missing teeth (where applicable), or damage. Wheel bearings should also be inspected for excessive play or incorrect installation that could affect sensor signal quality. Circuit continuity, voltage drop, insulation integrity, and resistance tests should be performed to identify electrical faults. Manufacturer diagnostic procedures may also include oscilloscope waveform analysis, sensor air-gap measurement, ABS module communication testing, CAN Bus diagnostics, and verification of the ABS module power supply and ground circuits.

For vehicles operating in New Zealand, following OEM diagnostic procedures helps accurately distinguish between a faulty wheel speed sensor, damaged encoder ring, wheel bearing problem, wiring fault, ABS control module issue, or communication fault before replacing expensive braking or stability control components.

Accurately diagnosing this fault often requires manufacturer testing procedures, wiring diagrams, ABS system schematics, connector pinouts, wheel speed sensor specifications, encoder ring inspection procedures, oscilloscope waveform examples, ABS module diagnostic routines, CAN Bus communication procedures, live data reference values, and system calibration information. Access to the factory service manual significantly reduces diagnostic time and helps prevent unnecessary parts replacement.

Applicable Years

2024, 2025, 2026, onwards

To order the correct OEM Service and Repair Manual for your MG ZS, submit your request using the form below, and our team will provide the ordering details.