While most of the automotive press was running around the New York auto show yesterday, Tesla issued a recall for 123,000 Model S electric vehicles. The recall addresses a problem with Model S sedans built before April 2016—specifically, with the bolts used in the power steering system. Tesla explained the issue in a letter to affected owners:

We have observed excessive corrosion in the power steering bolts, though only in very cold climates, particularly those that frequently use calcium or magnesium road salts, rather than sodium chloride (table salt). Nonetheless, Tesla plans to replace all early Model S power steering bolts in all climates worldwide to account for the possibility that the vehicle may later be used in a highly corrosive environment. If the bolts fail, the driver is still able to steer the car, but increased force is required due to loss or reduction of power assist. This primarily makes the car harder to drive at low speeds and for parallel parking, but does not materially affect control at high speed, where only small steering wheel force is needed.

It is the biggest recall Tesla has had to issue, affecting around (or maybe a little more than) half of all Model S vehicles built to date. In 2015, the company had to recall 90,000 cars for a seat belt problem, and in 2016 another 53,000 vehicles had to have their parking brakes replaced.

It's yet more bad news for the company in a week where its share price fell by 14 percent and its debt rating was downgraded.