Tyler Reddick suffered power steering issues at the Toyota/Save Mart 350 at Sonoma Raceway on June 28, finishing last in the 36-car field.
What happened?
Reddick's No. 45 Toyota had problems with the steering and power steering going in and out, making it hard to make any kind of lap time.
Billy Scott, crew chief of the No. 45 Toyota, told NASCAR.com that they don't really know what the issue was.
Why it matters for Tyler Reddick
The issue cost Reddick a solid top-10 day, and he was disappointed to not get many points on the day.
Reddick said it was a very odd issue, and everything seemed fine when they left the pit stall that first green-flag cycle.
What comes next?
Denny Hamlin now leads the regular-season championship by one point, after finishing 26th in the race.
Hamlin was a contender throughout the road-course race, spending much of the opening two stages inside the top six.
The plan was to sacrifice stage points by flipping both stages in exchange for track position over the final stint, but Hamlin was tagged from behind by Carson Hocevar in a restart on Lap 64.
Chris Gayle, crew chief for the No. 11, knew the possible repercussions of not collecting stage points.
Gayle said he's more proud of the fact that Denny stayed in it at the end, and they picked up nine spots.
Reddick will look to bounce back from this setback in the next race, as the battle for the top spot continues.
The NASCAR Cup Series will resume on July 5, with Reddick looking to regain the lead.