UK Buyer Reliability Guide4 Known Faults Documented

BMW i3 (I01) Common Problems & Reliability

The i3 was a radical departure for BMW, featuring a carbon-fibre reinforced plastic (CFRP) cell and an aluminium chassis. In the UK, it has a dedicated following. Buyers should choose between the pure BEV or the REx (Range Extender) model, which adds a small petrol engine for peace of mind but also more maintenance requirements.

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Generation Periods
4
Known Issues
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Critical Faults
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Moderate Issues

Select a Model Year Period

Detailed fault breakdown, symptoms, and estimated repair bills by production year.

Most Common BMW i3 (I01) Faults & Repair Costs

Moderate Risk

REx Engine Corrosion & Misfires

Est. Cost£500–£1,500

The Range Extender (a 650cc scooter engine) can suffer from internal corrosion or stale fuel if not used regularly. It is sensitive to spark plug and oil condition.

Warning Signs:

REx engine refusing to start, Rough running or "Drivetrain" error when the REx is active, Strong smell of petrol or oil

High Risk

Motor Mount & Bolt Failure

Est. Cost£1,000–£2,000

Early models had plastic motor mounts or weak mounting bolts that could snap under the high torque of the electric motor, potentially damaging the drivetrain.

Warning Signs:

Loud "thump" or bang under hard acceleration or regenerative braking, Vibration through the cabin

High Risk

KLE (Onboard Charger) Failure

Est. Cost£1,000–£2,500

The Convenience Charging Electronics (KLE) module can fail, leading to reduced AC charging speeds or a total inability to charge from a wallbox.

Warning Signs:

AC charging restricted to 3.7kW (half speed), Car refusing to start an AC charge, Fault message on iDrive

Low Risk

12V Auxiliary Battery Failure

Est. Cost£150–£250

The small 12v battery powers the car's computers. When it fails, the car throws dozens of unrelated error codes and may refuse to engage the high-voltage system.

Warning Signs:

Random "High Voltage System" errors, Car won't "Ready" or unlock, Screen glitches

Essential Pre-Purchase Step

Buying a used BMW i3 (I01)? Always check for hidden finance and write-off history.

Mechanical problems are only half the battle. Over 1 in 3 UK used cars checked have unpaid finance or accident write-off records that could cause you to lose the car or thousands in value.

Inspection Checklist for BMW i3 (I01) Buyers

On REx models, ensure the petrol engine starts and runs smoothly; many are never used and can seize or corrode internally
Check the custom narrow Bridgestone Ecopia tyres for wear; they are expensive and can wear quickly on the rear
Inspect the CFRP door sills and the plastic body panels for any cracks or structural damage
Verify the high-voltage battery capacity via the hidden service menu to ensure it hasn't degraded excessively