2021 BMW 540i Service and Repair Manual

This factory service and repair manual for the 2021 BMW 540i covers the year the sedan gained its 48-volt hardware: the engine is listed as a 3.0L inline-six mild hybrid, DOHC and turbocharged on gasoline, in a four-door sedan body sold in Base trim. A starter-generator and its high-current battery circuit sit alongside the conventional twelve-volt system, so the electrical sections matter as much here as the mechanical ones, and both are given with their own diagrams and specifications.

Engines covered

• 3.0L inline-six mild hybrid — DOHC, turbocharged, gasoline

Body styles covered

• 4-door sedan

Trims covered

• Base

Known issues on the 2021 540i. Six recalls are on the federal record for this year. One covers a badly assembled connection between the 48-volt battery and the starter-generator, where added electrical resistance can raise the risk of a fire. Two concern the drive to the rear wheels: output shafts that can break after a heat-treatment error, and a driveshaft-to-differential joint that can be damaged, either one able to cut drive or let a parked car roll away. Two more cover a rearview camera image that can be partly obscured, and one a seat belt retractor that may not work as intended in a crash.