MG4 rear motor (LFP)
2022–2026 · electric · 204hp
Engine codes: EH32
Reliability, common problems and owner reviews for the Mg MG4 MG4 rear motor (LFP). Check this before you buy used.
EH32 is the platform code, not a motor part number. The rear motor and the LFP pack are not what the MG4 forum is full of. MGEVs thread 16053: the two 12V faults owners keep separating are terminals left loose at pre-delivery — early cars were shipped with the battery unhooked for the boat, and the clamps were not always tightened — and software that did not let the traction pack top the 12V up unless the car was driving or plugged in. A later gateway update is what owners say changed the second one. Resting voltage on a healthy car in those threads sits around 12.5–12.8 V and rises to about 14.2–14.4 V while it is being charged, so a charger that stops there is the car working, not a reason to fit a lithium battery the DC-DC was not set up for. One owner was told by the AA patrol that the Chinese 12V batteries were poor; a Bosch was fitted and the dealer refunded it, and that car then stayed reliable for two years. That is one patrol's opinion and one cure, not a rule that every factory battery is scrap. Thread 26062 is a single Urban that still died after a battery test and a parasitic-drain test both passed. Separately, the plastic undertray sags or splits. MG's own bulletin is titled 'Subframe lower guard to battery gap', and dealers were told to fix it when the customer complains. One UK car shed the tray at 70 mph. The motor is the quiet part.
Known Issues
MGEVs 16053 and 13514. A flat 12V and the contactors never close: warning cascade (lane assist, collision, heavy steering), then a car with dark screens. Early cars: the terminal clamps were not tightened when the battery was reconnected after shipping. The second fault is software. Until the update, owners measured the 12V charging only while driving or while the traction pack was on charge, so a fortnight in an airport car park flattened it. After the update, early-car owners report 14 V on the app even after the car has sat for a couple of days. A deeply discharged lead-acid battery often will not recover; the replacement is the usual end of the story. Do not fit a lithium 12V. The DC-DC on these cars is discussed as finishing the charge around 14.2–14.4 V, which is a lead-acid figure.
Fix / Workaround: Open the bonnet and try the clamps with a spanner. Leave the car locked for several days and see if it opens. The invoice should name the 12V-maintenance software. A car that needs a jump every Monday is not fixed by another jump.
0Typically appears after: 5,000 km
MGEVs threads 7796, 15167 and 15230. The lower guard under the rear motor dips until it looks as if the unit is pushing through it. MG UK told at least one owner there was no manufacturing fault and would not pay. Other owners found a bulletin, 'Subframe lower guard to battery gap', which tells the dealer to repair it if the customer asks — it is not an automatic recall. A UK driver lost the tray at 70 mph on a motorway and was quoted a two-month wait, with warranty refused until argued. It is a plastic panel. It is also the panel under the drive unit, and a piece of it in the wheel arch is not a cosmetic scuff.
Fix / Workaround: Look under the rear bumper on the test. A dip, a split or missing clips is the bulletin. Ask for the guard to be refitted before you take the car, and keep the photos.
0Typically appears after: 5,000 km
MGEVs 26062, May 2026. An Urban was jump-started, the traction pack was filled, the dealer said the battery test and the drain test were both normal, and the car was dead again the next morning. That owner could not find the same pattern on other Urbans. It is one car with an open diagnosis, not the mechanism behind the earlier fleet of loose terminals. Do not explain every flat MG4 with a theory about an app polling the car.
Fix / Workaround: If the 12V is new, the clamps are tight and the software is current, and the car still dies, it is this sort of case. It wants a dealer log, not another battery on speculation.
0Typically appears after: 10,000 km
Year Cutoffs
Mileage Thresholds
After 15,000 km: 12V software and the clamps. The undertray is visible from day one.
After 80,000 km: No traction-motor or LFP-pack replacement pattern in the threads read for this pass.
Pre-Purchase Checklist
- ☐12V clamps tight, and the maintenance software named on the invoice
- ☐Leave it parked, then see if it opens and the screens light
- ☐Resting voltage around 12.6 V, about 14.2 V after a drive — do not fit a lithium 12V
- ☐Undertray flat, clipped, not split; ask for the subframe-guard bulletin if it is not
- ☐One DC charge
- ☐A hum from the motor is not the 12V problem — listen for it separately
Frequently asked questions
Is the Mg MG4 MG4 rear motor (LFP) reliable?
Maint. Sensitive — EH32 is the platform code, not a motor part number. The rear motor and the LFP pack are not what the MG4 forum is full of. MGEVs thread 16053: the two 12V faults owners keep separating are terminals left loose at pre-delivery — early cars were shipped with the battery unhooked for the boat, and the clamps were not always tightened — and software that did not let the traction pack top the 12V up unless the car was driving or plugged in. A later gateway update is what owners say changed the second one. Resting voltage on a healthy car in those threads sits around 12.5–12.8 V and rises to about 14.2–14.4 V while it is being charged, so a charger that stops there is the car working, not a reason to fit a lithium battery the DC-DC was not set up for. One owner was told by the AA patrol that the Chinese 12V batteries were poor; a Bosch was fitted and the dealer refunded it, and that car then stayed reliable for two years. That is one patrol's opinion and one cure, not a rule that every factory battery is scrap. Thread 26062 is a single Urban that still died after a battery test and a parasitic-drain test both passed. Separately, the plastic undertray sags or splits. MG's own bulletin is titled 'Subframe lower guard to battery gap', and dealers were told to fix it when the customer complains. One UK car shed the tray at 70 mph. The motor is the quiet part.
What are the common problems and reviews for the Mg MG4 MG4 rear motor (LFP)?
The most commonly reported problems: 12V goes flat: loose clamps, or the car never tops it up, Undertray sags, and one split at motorway speed, One Urban still died after the battery tested fine.
Is a used Mg MG4 MG4 rear motor (LFP) worth buying?
Fine if serviced correctly — but it punishes neglect hard. History and the right consumables matter.