The four-time champion progressed from the original half-hour qualifying session into the top-10 shootout, where he ended up seventh at the wheel of his BMW 330e M Sport.
But Turkington was later excluded after it was found that there was an insufficient sample size in the car for a fuel test.
The catalyst for the error was a red flag after 10 minutes of the first qualifying session, caused by Will Powell spinning his Honda into the gravel at Druids.
Teams are not allowed to refuel their cars after the original qualifying session begins.
WSR team principal Dick Bennetts told Autosport: “It was just a miscalculation.
“When the red flag came out, Colin had just gone green in sector one.
“We normally would have put his second set of tyres on at that point, but because he’d just gone green we knew the tyres were still good, but when he went back out with the same tyres he couldn’t do a better time.
“Because of that he did an extra four laps, and that made the difference.
“The car is still overweight, so it’s a tough thing to happen.”
Source: Autosport