MG ZS (Gen2) Ignition Coil Fault

An Ignition Coil Fault indicates that the Engine Control Module (ECM) has detected an abnormality in one or more ignition coils or their control circuits. The ignition coils convert the vehicle’s low battery voltage into the high voltage required to ignite the air-fuel mixture within each cylinder. Modern MG ZS Gen2 engines use a coil-on-plug (COP) ignition system, where each spark plug is supplied by its own dedicated ignition coil for precise ignition timing and improved engine efficiency. A faulty ignition coil can cause incomplete combustion, resulting in engine misfires, rough running, reduced power, increased fuel consumption, and higher exhaust emissions. This fault applies to the MG ZS Gen2 (ZS11 platform), introduced from 2024 onwards.

Symptoms

  • Check Engine Light illuminated
  • Engine misfire
  • Rough or unstable idle
  • Poor acceleration
  • Loss of engine power
  • Engine hesitation
  • Increased fuel consumption
  • Hard starting
  • Engine shaking or vibration
  • Engine stalling
  • Strong fuel smell from the exhaust
  • Ignition coil or cylinder misfire-related Diagnostic Trouble Codes (DTCs) stored

Possible Causes

  • Faulty ignition coil
  • Internal ignition coil insulation breakdown
  • Failed ignition coil primary or secondary winding
  • Worn or faulty spark plugs
  • Damaged ignition coil boot
  • Moisture or oil contamination in the spark plug well
  • Open circuit in the ignition coil wiring
  • Short circuit to ground or battery voltage
  • Loose, damaged, or corroded electrical connectors
  • Poor power supply or ground circuit
  • Engine Control Module (ECM) driver circuit fault
  • Faulty Engine Control Module (ECM) (rare)

Diagnosis

Diagnosis begins by confirming any stored Diagnostic Trouble Codes (DTCs) and reviewing freeze-frame and live data using a compatible diagnostic scan tool. Live data should be monitored for cylinder misfire counts, engine speed, ignition timing, fuel trim values, and individual cylinder performance. The technician should identify the affected cylinder(s) and inspect the ignition coil, spark plug, ignition coil boot, and spark plug well for oil contamination, moisture, cracks, carbon tracking, overheating, or physical damage. The ignition coil wiring, connectors, power supply, ground circuits, and ECM control circuits should be inspected for corrosion, loose terminals, damaged insulation, or wiring faults. Circuit continuity, voltage drop, and resistance tests should be performed to identify electrical faults. Manufacturer diagnostic procedures may also include ignition coil swap testing, spark output testing, oscilloscope waveform analysis, ECM driver circuit verification, injector balance testing, compression testing, and cylinder leak-down testing where required to eliminate mechanical engine faults.

For vehicles operating in New Zealand, following OEM diagnostic procedures helps accurately distinguish between a faulty ignition coil, worn spark plug, wiring problem, ECM driver fault, injector issue, or engine mechanical problem before replacing expensive ignition system components.

Accurately diagnosing this fault often requires manufacturer testing procedures, wiring diagrams, ignition system schematics, connector pinouts, ignition coil specifications, spark plug specifications, ECM driver circuit information, oscilloscope waveform examples, cylinder misfire diagnostic 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.