Model Sbuyer's guide

The MCU1 eMMC failure on pre-2018 Model S is a $1,500–$2,500 repair that kills the touchscreen and can leave you locked out of climate control mid-winter. This guide shows you exactly how to check whether the unit has been replaced or is about to fail — and what other faults to watch for across the full 2012–2021 production run.

This guide covers 13 documented faults: MCU1 eMMC chip failure, drive unit bearing wear, 12V battery failure (a common stranding event), air suspension bladder failure, door handle retraction failure, panoramic roof rattles and seal degradation, HVAC issues on early builds, high-voltage cable corrosion, battery coolant leak, charge port latch failure, rear motor seal leak, touchscreen wifi antenna failure, and autopilot camera delamination on later cars. Each entry explains what the fault looks like, how to check for it, and real-world repair costs.

Works equally well on a dealer forecourt or a private sale. No tools needed — just this guide and your phone.