C43 Fun Haver

Had a CEL pop on the other day, FIRST code P044200, replaced fuel cap, clear code & hasn't come back on
2nd code was P035596, changed coil #5 and cleared code & hasn't come back on.
3rd code P023409- Boost pressure turbo 1 too high. started with blowing out the vacuum line from the pressure transducer Y77/1 to the vacuum pump, vacuum line was filled with oil.
changed the vacuum pump, pressure solenoid and blow out the vacuum lines.
cleared codes
duty cycle before and after
before part replacement.
5% actual 65-97 target

after
74% actual 65-97 target

went for a few long drives over the weekend, boost pressure seems to be happy again

datbananaguy

Some time ago I started to have power issues with my 2016 G500 with M176 engine. Sudden power loss and limp mode on hard acceleration, no CEL. Problem goes away immediately after ignition cycling OFF/ON. Initially the problem occurred once during a month, next month it was three times, and then almost every acceleration lead to power loss and limp mode. Since the problem was getting worse gradually, I assumed a mechanical issue rather than electric. Specifically I suspected that wastegate/wastegate actuator was going bad.

Xentry scan revealed error code "P023409 - The boost pressure of turbocharger 1 is too high. There is a component fault."

Repair steps/logic:
Usual suspects (in this case): pressure sensors - checked, OK; vacuum hoses - checked, clean and no leaks, OK; blow-off valves - checked, OK; wastegate actuator stuck - possible, but not probable since the car has less than 10 thousand miles and ECU actually opens them when entering limp mode, so before disassembling turbos we decided to check remaining to components in the system: vacuum pump - no oil found in hose to pressure transducer, assumed that pump is OK; boost pressure transducer (Y77/1) - ordered a new part from MB, changed, problem went away.