BMW i-Series Service and Maintenance

BMW i3 Service and Maintenance

The BMW i3 has reached an age where it is an opportunity for European specialists. The i3 is an electric vehicle with an optional range-extending gasoline engine. The first model year was 2014, and the last year was 2021. More than 45,000 were sold in the US.

The uni-body of the i3 is made from carbonfiber-reinforced plastic. The electric motor, range-extending engine and battery are mounted to an aluminum subframe. The front suspension is mounted to the carbon fiber unibody using an aluminum subframe.

The i3 has the same maintenance and service opportunities as many other BMWs, hybrids and electric vehicles. Here are just a few items and tips for the i3.  

Lifting and i3

The i3 requires lift pads that fit into four holes in the underbody. The sharp edges on some lift pads can damage the carbon fiber structure. When spotting the car on the lift, position the center of gravity in the middle of the lift because most of the weight is in the rear.

W20 Range-Extending Engine

Most i3 models you will encounter have a two-cylinder engine coupled to a generator for the high-voltage battery system. The 650cc two-cylinder engine is not connected to the drive wheels. The W20 engine is from Kymco and is used in the BMW C650 GT scooter. The fuel tank can hold 2.7 gallons and is located in the front. 

The engine runs between 2,200- and 4,300 rpm. The engine speed is dependent on the state of charge of the battery. The engine has two counterbalance shafts to eliminate vibration. In addition, the engine has a stop/start function that will not run the engine while at a stoplight. The goal is to mask the sound and vibration of the engine with road noise.

If you need to perform diagnostics on the engine, some enhanced and factory scan tools can start the engine while the vehicle is parked.

Tire Rotation

The i3 has both 19- and 20-inch wheel and tire packages. The front tires use a skinny 155mm wide tire. The rear uses a 175mm wide rear tire. Rotating the tires is not possible. Also, owners are limited on replacement tire options. Always make it a point to inspect the tires, so a wear problem does not result in a premature tire failure and potentially a long wait for a replacement tire.

Oil Changes

Models with the range-extending engine require regular oil and filter changes. The interval is regulated using condition-based service (CBS) monitors that typically require a change every 12 months or 10,000 miles. The oil viscosity is 5w30, and it should meet BMW’s Long-Life specifications. The oil capacity is only 2.75 quarts; do not overfill. 

To avoid removing the entire panel in the trunk, you can pour or pump the oil through the dipstick tube under the plastic access plug. But, removing the panel also gives you access to the cooling system expansion tank.

If you do any programming, record the oil life index before the procedure. Often, the oil life will reset to 100 percent after programming. A scan tool makes it possible to set the oil life index to the correct level.


The cabin filter can be accessed in the passenger footwell on the side of the center console. There are two cabin air filters stacked on top of each other.

There is no serviceable engine air filter. The housing containing the filter and silencer for the air intake must be serviced as a complete unit. BMW claims the engine air filter should last the vehicle’s life. 


The i3 has had many software updates to address problems encountered in the field. Many of the updates were implemented after 2019. The updates can cure problems with charging, range-extending engine performance and the displays inside the vehicle. Even if there isn’t a problem, check for the latest calibrations and updates. 

According to one TSB, later updates change the sound of the electric motor. It is not the actual sound of the electric motor, but a simulated sound played through the speakers. The changes are to the tone and pitch. Customers may notice the difference.

12-Volt Battery

All i3s have a 12-volt battery in the front compartment. The high-voltage battery and range-extending engine charge the 12-volt battery. If the battery is weak, it can cause high-voltage battery charging issues and a reduced range. A weak battery can also affect the operation of the electric power steering. As a result, the driver might notice a reduction of steering assistance sporadically during certain driving situations. 

Allowing a vehicle’s battery voltage to drop below 12.0 volts (12.0V) permanently reduces the battery life expectancy and can lead to premature battery failure and possibly impact the life of the high-voltage battery. If the battery is below 71 percent or 12.5-volts, recharge and test the battery. 

On most BMW hybrid/electric vehicles, the battery must be charged if the SoC is below 25 percent or one or fewer blue bars are present on the state of charge display. You can check the instrument cluster for battery-related check control messages to determine the condition of the 12V battery. If a new battery is installed, make sure to reset the battery monitor. 

Motor Mounts

The electric motor in the i3 produces instant torque, and there is not a clutch or torque converter to cushion the blow. As a result, the three electric motor mounts in the rear are under a lot of stress. Upper mounts can be inspected by removing the rear wheels and inner fender liners. The lower mount is a dog bone that can be seen under the vehicle. Inspect the mounts for any damage that might include cracking and separation from the housing.

Some 2014 models had software updates to reduce stress on the mounts. Mount damage occurred during acceleration when there was a sudden loss of traction. TSB SI B22 04 15 includes information for inspection and installation of new mounts. 


Always inspect the brakes on the i3 when it is in for service. The pads wear just like any other vehicle. The biggest issue with the brakes is noise. Since the electric motor and gasoline engine are almost silent, any brake noise will be heard by the customer. Using a high-quality brake pad is a requirement of any brake job.

Some models use BMW’s lightweight composite rotors that use a hat that attaches to the friction ring with pins. Microscopic movements of the interface between the hat and the wheel bearing flange can cause a clicking noise when the brakes are not applied. The BMW solution is to install a friction ring between the rotor and flange. The other solution is to install a solid replacement rotor.

You May Also Like

VarioCam: Understanding Porsche’s VVT Technology

Originally developed for the 2001 Porsche 911 Turbo, VarioCam changes the valve timing to increase power & reduce emissions.

VarioCam and VarioCam Plus are Porsche’s patented variable valve timing and valve lift technologies that have evolved over the past two decades. Originally developed for the 2001 Porsche 911 Turbo, VarioCam changes the valve timing to increase power and reduce emissions. 

VarioCam Plus on later models can adjust valve lift by controlling oil to the upper part of the lifter. The lifter can ride on two different profiles on the camshaft. But, the oil passages can become clogged if an oil change is neglected.

Mercedes 4MATIC Diagnostics

The Mercedes-Benz 4MATIC all-wheel drive (AWD) systems have been around for a while now.

Mercedes-Benz Auxiliary Water Pump Diagnostics

These pumps will show up on more and more vehicles as engines become more efficient and generate less excess heat.

Timing BMW VANOS N53 And N54 

To service them, you will need the appropriate toolset to lock the crank and camshaft.

Jaguar V6 Timing Chain Service

When a guide and tensioner fail, it induces timing chain slap that causes the chain to jump on the sprockets.

Other Posts

Active Suspension Service 

An active dampener allows for a ride without compromise.

Volvo Engine Service

There are many combinations for the Volvo modular engine.

Servicing Mercedes-Benz AMG Brakes

Take a look at some of the things you need to know in order to service the brakes on a Mercedes-Benz AMG vehicle.

AUDI Outside Air Temperature Readings

Incorrect readings can be avoided.