TCR's control ECU requiring more work than expected prompted Volkswagen to abandon its early use of the part in the World Touring Car Cup a year before its universal introduction.
All four of Sebastien Loeb Racing's Volkswagen Golf GTIs were fitted with the Magneti Marelli ECU for the start of the 2019 WTCR season, but Volkswagen took the decision to revert to its standard road car control unit for the third round of the season in Slovakia.
At that point, Rob Huff was the team's highest-placed driver in 13th while double World Rallycross champion Johan Kristoffersson, rookie Benjamin Leuchter and WTCR race winner Mehdi Bennani occupied three of the bottom four places in the points standings.
Volkswagen motorsport director Sven Smeets told Autosport the brand originally chose to run the part in the hope of having a head-start on its competitors when the standard ECU is fitted to all cars competing in TCR series next year.
"The ECUs we are driving today come from the standard car, they are standard ECUs, and we know also that we are not always in the optimised situation in every race," said Smeets.
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"[The reason] we decided to go for the new ECU for next year is that we then had one year under the belt with the new ECU when it was introduced in racing for everybody.
"Unfortunately the timeframe was too short for the work that there was to do.
"If we would have had one month more before [the season opener at] Marrakech, then I think it would have been fine, and if we were able to do something during the races to bring it where it has to be, then that would have been also fine.
"But of course once the race season starts you can't just start changing mappings all the time."
All four WTCR Golfs were saddled with the maximum 60 kilograms of compensation weight for the Slovakia round for changing ECUs, a figure that was reduced to 30kg for the fourth meeting of the season at Zandvoort in May.
Leuchter and Kristoffersson scored the first Volkswagen podiums of the season that weekend by finishing second and third respectively in the reversed-grid race, while both won at the Nurburgring a month later.
Smeets said the decision to ditch the ECU was a "difficult situation because we knew we were not very far off" with its development.
"But the thing was we knew it was never going to be perfect, and then it's still very difficult [to make a call]," he added.
"The drivers also said, 'Yeah, maybe it's better to go back to what we know'.
"We know it's also not top, but we won some races last year with it, [and now] we have won some races this year with it."