sn202020

My 240,000km glc300 got CEL of P0299, turbocharger underboost code, when I try faster than 120km/h.

Googling found it could be theTurbocharger wastegate actuator, and tested the actuator with a vacuum pump. Indeed, the vacuum was leak and only move 4mm actuator rod at 5psi.

​i ordered cheap Ali's A2740904380 (with rod length 19.6mm) for $33.
I received and installed new part, the vacuum moves 17mm rod at 15psi without leaks. E-ring removal and installation was hardest.

kjb55

Thanks for posting. Like the green tape to the cir-clip trick.

mikapen

Definitely!
Thanks @sn202020 for something that goes in my bag of tricks.