Despite dominating most of the weekend and being a net second ahead of the field per lap Mercedes needed to leave Montreal with a bittersweet feeling. It is now understood that minor changes in the team's procedures have been undertaken to prevent any repeat of the ERS issue.
The reliability issues plagued both cars in Canada two week ago, resulting in a DNF for Lewis Hamilton and Nico Rosberg being deemed for a cruising mode.
After a careful analysis Mercedes engineers found out the root of the issues: due to the extremely hot weather experienced in Canada some of the components such as the electronic unit which controls the MGU-K overheated. In fact, the CE-CUK got too hot and some of it got burnt down. Thus there was no way to try and reload the systems. Mercedes technical chiefs conceded the control unit box burnt down exactly at the maximum temperature level it was defined while being designed. Due to the dysfunction of this unit the MGU-K shut down, hence the drivers were not able to harvest 160 horse power from the KERS.
Mercedes were not sure about the problems and why they arose at Canada and not in Malaysia or Bahrain where the teams had to cope with even hotter ambient temperatures. They were running test at the dyno at Brixworth to be able to avoid the reappearance of the problem next time round. Is was identified the special aero package aimed for Montreal and a new cooling system were to blame.
The electronic control units cannot be used any more over the course of the remainder of the season. Both drivers will use their third set in Austria which means they will have two new ones to complete the season without being hit by grid-penalties.