MG MG3: Hybrid+ sudden power loss when traction battery nears depletion

The MG3 Hybrid+ shares its powertrain with the ZS Hybrid+, which can dramatically cut power delivery when the small hybrid battery nears depletion — leaving too little performance to overtake safely or climb a long hill. MG rolled out a free dealer software update for the ZS Hybrid+ in early 2025 that keeps the battery at a moderate state of charge, but CarExpert reported the MG3 version of the fix lagged behind, so individual cars may or may not have received it. It is a software campaign, not a recall, so completion is not tracked on recall databases.

• Sudden loss of acceleration on long hills or motorway overtakes
• Power fades when battery gauge is near empty
• Engine revs hard with little forward progress

1. 1

   Test drive with the hybrid battery gauge low if possible: find a decent hill or motorway on-ramp and accelerate hard, feeling for the power falling away.

2. 2

   Check the infotainment software version screen and ask the dealer to confirm the hybrid powertrain update has been applied.

$0 to $300 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the hybrid powertrain software update been applied at an MG dealer?”
• “Have you ever experienced sudden power loss on hills or overtaking?”
• “Is the balance of the MG NZ new-car warranty transferable?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.