Technical Service Bulletin B340521 — 2020 BMW 840I
EQUIPMENT ADAPTIVE/MOBILITY
Bulletin Details
| TSB ID | B340521 |
| Manufacturer | |
| Vehicle | 2020 BMW 840I |
| Component | EQUIPMENT ADAPTIVE/MOBILITY |
| Communication Date |
Bulletin Summary
Diagnosis of Compound Brake System Complaints in M Vehicles: 1. Visible cracks are caused by high thermal stresses during rapid heating and cooling of the brake discs. Braking from high speed with cold brake components (less than 212 degrees F) increases the likelihood of cracks to form.
About Technical Service Bulletins
A Technical Service Bulletin (TSB) is a document issued by a vehicle manufacturer to its dealers, describing a known issue with a specific vehicle or set of vehicles and the recommended procedure to fix it. Unlike recalls, TSBs are not mandatory and are typically only performed if an owner reports the related issue. However, TSBs can be an indicator of common problems with a vehicle.