McLaren and engine partner Honda have been forced to change their power unit on the opening day of the second pre-season test following yet further issues for the team which has so far struggled for reliability.
McLaren endured a tough opening test which saw the team get through at least four power units across four days, with a number issues to blame, including an oil tank that needed resizing and an as yet unspecificed problem.
Stoffel Vandoorne managed just 34 laps on Tuesday before Honda "detected an electrical issue" and chose to replace the unit for a new one.
"In the interests of maximising lap time, we sped to replace the power-unit and investigate the issue further once it is out of the car," a spokesperson said.
"The PU we are using is the same specification as the one run at the test last week."
Honda are planning on introducing a new power unit at the opening race in Australia and it's believed they will run it at some point this week, though it's not clear whether it addresses the ongoing reliability problems, or is simply an upgraded unit aimed at delivering more performance.
