An investigation of Tesla power steering problems was this week upgraded to an engineering analysis after initial probing turned up thousands more failures.

The National Highway Traffic Safety Administration (NHTSA) began inspecting power steering failures in 2023 Tesla Model 3 and Y vehicles in late July after receiving 12 complaints. In the subsequent six months, the NHTSA received an additional 103 complaints, and with Tesla's help has identified an additional 2,176 incidents in which power steering in the vehicles failed partially or completely, the regulator said [PDF].

Not including duplicates, a total of 2,191 power steering failure incidents have now been identified.

"A majority of allegations reported seeing a warning message, 'Steering assist reduced,' either before, during or after the loss of steering control. A portion of drivers described that their steering began to feel 'notchy' or 'clicky' either prior to or just after the incident," the NHTSA reported.

According to a summary of the NHTSA's research over the past six months, the power steering outages occurred both at startup and during operation, at various speeds and in various locations. 

"There have been multiple allegations of drivers blocking intersections and/or roadways," NHTSA said. "ODI is aware of over 50 vehicles which were allegedly towed as a result of the condition from a variety of areas including, driveways, parking lots, side of road and intersections."

In multiple instances, complainants said they were able to remedy the situation by turning their Muskmobile off and on again, but the fix was temporary and only a steering rack replacement was able to fully resolve the issue.

It appears the NHTSA is homing in on the steering racks as the cause of the issue, with Tesla supplying four steering rack part numbers to the NHTSA for its investigation. Two of the steering racks identified by Tesla were found in 2,187 of the complaints, with the remaining four reports not including a part number. The NHTSA believes some 334,569 vehicles may be affected.

It's not clear if the NHTSA is also looking into Tesla software as part of the engineering analysis; we asked, but the agency declined to comment citing the ongoing nature of its investigation. 

An NHTSA engineering analysis is the final step before a potential recall - much like the one that was also reported today involving [PDF] improper font sizes on warning indicators for brake, parking and antilock brake systems. According to the NHTSA, Tesla began fixing the issue, which affected 100 percent of vehicles, with an OTA software update late last month. 

The warning font size recall is the second universal Tesla recall in the past three months, with the company releasing a software update in December to add new safety features to Autopilot after the NHTSA determined its existing safety controls were "insufficient to prevent misuse." 

Tesla didn't respond to questions from The Register for this story. ®

https://www.theregister.com//2024/02/02/tesla_power_steering_probe_upgraded/