MG Marvel R EP21 — Problems & Common Faults
Weaknesses, engine ratings and buying advice
The MG Marvel R (EP21) arrived in Europe in October 2021 as one of MG's first fully electric SUV coupes and remained on sale until mid-2025. It is powered by permanent-magnet synchronous motors with a nickel-cobalt-manganese battery (66.1 kWh net): the base version drives the rear axle with 132 kW, while the top version delivers 212 kW to all four wheels. ADAC's test of the all-wheel-drive version returned a good overall grade of 2.4, with the drivetrain scoring particularly well while handling and running costs were only average. The Marvel R's strengths are a smooth, strong drivetrain, a interior that feels upscale for the price, and a generous 84-month/150,000 km warranty covering the whole vehicle including the high-voltage battery, which is covered down to 70 percent remaining capacity. When buying used, three recurring issues deserve close attention. First, on some vehicles the lane-keep and emergency-braking assist react too aggressively — MG itself acknowledges this as a known, not fully resolved design issue; a software update was offered but, per a documented case, brought no real improvement. A test drive paying attention to abrupt steering or braking interventions is therefore essential. Second, on some vehicles maximum DC charging power noticeably drops below the original figure of up to 92 kW after firmware updates, sometimes to 60-75 kW — a test charge at a fast charger provides clarity. Third, the 12-volt auxiliary battery tends to weaken under short-trip-only use because the high-voltage system does not consistently top it up; checking the battery voltage and occasionally using an external trickle charger prevents starting trouble. Smaller but documented individual points include a sticking lock pin at the charging socket, a door mirror that does not automatically return to the driving position after reversing, and faux leather wearing through on the seat bolsters — the latter was replaced free of charge under warranty after around 56,000 km in the documented case. The cell chemistry itself shows moderate, age-appropriate capacity loss in daily use with no notable outliers. For a used purchase, the 212 kW all-wheel-drive version is the more rounded choice thanks to smoother performance and extra traction, while the 132 kW base version works as a solid if unremarkable daily car. In any case, a fully up-to-date software status and a test drive that specifically checks the assistance systems and charging performance are important.
Engine Overview
The MG Marvel R EP21 is available with 2 engine variants — from 180 to 288 hp.
The drivetrain uses two permanent-magnet synchronous machines (PMSM) on the rear axle, fed by a nickel-cobalt-manganese battery (NCM). PMSM technology is brushless and mechanically simple, so genuine motor failures are rare. The more sensitive area is the periphery: on some vehicles the maximum DC fast-charging power drops noticeably below the original figure after software updates, so a test charge is worthwhile when buying used. In addition, the 12-volt auxiliary battery drains faster than usual under mostly short-trip use, since the high-voltage system does not consistently top it up — an occasional external trickle charge prevents it from going flat. The cell chemistry itself shows moderate, age-typical capacity loss in daily use without notable outliers.
- ! DC charging power drops after software updates
Several vehicles reach noticeably less than the originally achieved fast-charging power of up to 92 kW after firmware updates, sometimes only 60-75 kW.
Symptoms: The charging station consistently shows lower power figures than before the last software update, with no major difference in temperature or state of charge. - ! 12-volt battery drains under short-trip use
Under mostly short-trip use, the high-voltage system does not sufficiently recharge the 12-volt auxiliary battery, so it weakens faster than usual.
Symptoms: After a longer period of standing or many short trips, the vehicle becomes harder or impossible to start, and the battery indicator drops.
In the all-wheel-drive model, an additional permanent-magnet synchronous machine (PMSM) on the front axle supplements the rear-axle unit, supplied from the same nickel-cobalt-manganese battery (NCM). The extra drive unit barely adds complexity, since PMSM motors are brushless and low-maintenance — motor failures are the exception in practice. As with the rear-wheel-drive version, the more sensitive point is charging and auxiliary-battery management: on some vehicles maximum DC charging power noticeably declines after firmware updates, and the 12-volt battery is not reliably topped up under short-trip-only use, which can cause starting trouble. A test charge and a check of the battery voltage display are worthwhile when buying used.
- ! DC charging power drops after software updates
Several vehicles reach noticeably less than the originally achieved fast-charging power of up to 92 kW after firmware updates, sometimes only 60-75 kW.
Symptoms: The charging station consistently shows lower power figures than before the last software update, with no major difference in temperature or state of charge. - ! 12-volt battery drains under short-trip use
Under mostly short-trip use, the high-voltage system does not sufficiently recharge the 12-volt auxiliary battery, so it weakens faster than usual.
Symptoms: After a longer period of standing or many short trips, the vehicle becomes harder or impossible to start, and the battery indicator drops.
Compare across all models: Replacement costRiskMeasured ageing
Vehicle Weaknesses
| Weakness | Cost | |
|---|---|---|
| Lane-keep and emergency-brake assist react too aggressively The lane-keep assist intervenes harshly in the steering and is classified by MG itself as a known design issue. The emergency-braking assist occasionally triggers braking with no obstacle present. Symptoms: When overtaking or in residential streets with cars parked on both sides, the vehicle brakes abruptly or steers hard against the driver's input without a genuine obstacle. | Low | |
| Charge port lock sticks The locking pin at the charging socket can break or jam, so the charging gun can no longer be removed after charging. Symptoms: After charging ends, the CCS connector at the charging station cannot be unlocked and the car remains attached to the cable. | Low | |
| Door mirror stays folded in reverse position After reversing, the lowered door mirror does not automatically return to the normal driving position, usually affecting the right mirror. Symptoms: After engaging a forward gear, the mirror remains in the lowered reverse position and has to be corrected manually, either by hand or via the seat-memory button. | Low |
Test Reports
ADAC Autotest
ADAC's test of the all-wheel-drive version (212 kW) resulted in an overall grade of 2.4 (good). The drivetrain in particular scored 1.3, while handling and running costs were only mid-range. No defects or recalls were documented at the time of testing.
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Known Problems and Issues +
A total of 8 weaknesses have been documented for the MG Marvel R EP21 (2021–2025) — 4 engine-related and 4 vehicle-related. Typical issues affect Electronics, Interior. Considered reliable: MARVELR-EM-RWD (Elektromotor (Dual, Heck)), MARVELR-EM-AWD (Elektromotor (Triple, Allrad)).
What to watch out for with the MG Marvel R? See the detailed listing of all engine and vehicle weaknesses in the sections above.
Frequently Asked Questions
What problems and weaknesses does the MG Marvel R EP21 have? +
What should I look for when buying a used MG Marvel R EP21? +
Which engine is recommended? +
Which MG Marvel R EP21 engine is the most reliable? +
Which MG Marvel R EP21 engine is the most fun? +
Is the MG Marvel R EP21 worth buying used? +
What horsepower variants are available for the MG Marvel R EP21? +
Last updated: February 2026 · All information without guarantee