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.
Select a Model Year Period
Detailed fault breakdown, symptoms, and estimated repair bills by production year.
Most Common BMW i3 (I01) Faults & Repair Costs
REx Engine Corrosion & Misfires
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.
REx engine refusing to start, Rough running or "Drivetrain" error when the REx is active, Strong smell of petrol or oil
- Request a manual start of the REx (Maintenance Mode) during the test drive
- Check the oil and spark plug service history
- Look for fuel pressure sensor recall completion
Motor Mount & Bolt Failure
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.
Loud "thump" or bang under hard acceleration or regenerative braking, Vibration through the cabin
- Check if the upgraded aluminium mounts or stronger bolts have been fitted
- Inspect the motor area for any signs of movement or loose hardware
KLE (Onboard Charger) Failure
The Convenience Charging Electronics (KLE) module can fail, leading to reduced AC charging speeds or a total inability to charge from a wallbox.
AC charging restricted to 3.7kW (half speed), Car refusing to start an AC charge, Fault message on iDrive
- Test the car on a 7kW or 11kW AC charger and check the draw
- Check if the updated KLE unit was fitted under warranty
12V Auxiliary Battery Failure
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.
Random "High Voltage System" errors, Car won't "Ready" or unlock, Screen glitches
- Check the date code on the 12v battery (should be replaced every 4-5 years)
- If original, budget for immediate replacement
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.