In the Drive to Survive Netflix documentary that was launched in March earlier this year, Steiner and Grosjean's relationship was a focal point in the series, as the Frenchman struggled in the early part of the 2018 season.
The relationship was seen to be strenuous, but Steiner maintains that the two share a healthy relationship.
"Our relationship is pretty strong, otherwise we wouldn't have survived last year," Steiner said. "It's just we are in a difficult time."
Speaking ahead of the Spanish Grand Prix weekend, Steiner said it was a tough start to the year so far for Haas, who showed pace in qualifying, but was losing out in the race.
"We know we have a good car," he said. "We qualified out of four races three times in the top ten, which shows us that the car has the speed.
"We just need to make it work over a race distance and we'll be fine. When we start the race, after three laps we go a second and a half slower than everyone else."
Haas seemingly appeared to be on top of their issues in Barcelona, as it didn't have the graining problems it had at the preceding races.
Both Grosjean and teammate Kevin Magnussen qualified inside the top ten and crossed the line in the top ten, with Magnussen in seventh and Grosjean in tenth.
Magnussen has brought home the bulk of Haas' points at the first five races of the year, scoring 14 to Grosjean's single point.
"I haven't seen anything different, but that's a good question for him. I'm not out there racing," Steiner said.
Steiner also questioned the thinking behind some decisions to award penalty points, highlighting Grosjean's latest incident in Bahrain, where he impeded Lando Norris in qualifying which resulted in a three-place grid penalty and one penalty point.
"Sometimes with these points, the last one that Romain got was completely... he has a driver didn't do anything wrong," Steiner remarked.
"I disagree with the grid penalty, but I take that one more. But he actually as a driver did nothing wrong. The race engineer didn't tell him, and the circumstances were just confusing."