Sergio Perez was limited to under 40 laps during Saturday morning of testing, with Dr. Helmut Marko revealing the team had some engine problems during the session.
The Mexican and the team bounced back in the afternoon as he finished the day with 117 laps completed.
"We had some minor problems today in the morning which meant that Perez had to drive a little less," Marko told Sky Sports Deutschland.
When asked whether the issues were a mechanical or software problem, Marko revealed it was the former though he said there are no concerns moving forward.
"Mechanical problems can only really relate to the engine and the drivetrain," he added. "We were able to find out why we had those problems and it can easily be solved. We can just continue with the program."
That's what Red Bull did in the afternoon with Perez logging a healthy number of laps, though the team will be wondering what went wrong when the engine cover blew off the RB16B and caused a red flag.