911crash

Normally around town, supercharger works fine. Only when I’m cruising down the highway, for no identifiable reason, the supercharger stops working and it falls flat. So far, no real time codes, no historical codes. I’ve replaced I/c pump, iat sensor, fuel filter. I’ve also tried eliminating any cooling bubbles (if it had any). The car is super strong when it’s working. Fuel pump is next…. I know it has have 2 fuel pumps with one including the fuel level sensor. There is 1 funny thing. Fuel level never reads full. Scans were done using Mercedes STar dIag.
The only other electrical issue that I have yet to uncover is the heated seats don’t work. Is there a relay for the supercharger? SAM?

808C32AllMyGas

911crash their is a relay for the SC pump in the trunk Sam fuse box, SC should pull in the SC clutch at 2500 RMP. 1: Have you checked serpentine belt for slipping? 2: AIT data recorded? SC will drop out with high AIT. 3:Are you running a different SC pulley from stock/made changes? SC pulley gapping wrong? SC pulley clutch solenoid connector damaged/loose.
I've not run into this issue with either of my C32 AMG but Just a few ideas to consider when trouble shooting this issue, good luck!

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911crash

Thx for the reply. Everything is stock. New AIT. Connector is good. New belt and tensioner. SC works fine until I have constant load, ie cruising speeds, going uphill at freeway speed. No codes, recorded or in real time. I’ll pull the relay and replace. It’s so discouraging. I just got this car and suspect it was a problem for the previous owner, but it’s intermittent and seemed perfectly fine when I test drove it. I have few performance things I want to do, but until this is sorted I must remain focused. It’s a super clean car otherwise. Always maintained at the dealer
until 130k miles (158k now).

808C32AllMyGas

The SC coolant pump going out sounds more like your issue given the full load statement, in short pulls the coolant pump circuit is not under a lot of load, At full load the pump should be running all the time, if the pump is going out your SC coolant pump circuit coolant will get too hot cutting out the SC pulley. I have a Johnson CM30 pump installed in one vehicle and a after market in the other, the after market pump started failing and I had the SC disengage after a hard pull. swapped out the pump and it solved my issue. Checking the AIT with a bluetooth ODBII is the way to go and see what temp the air intake coolant circuit hits on hard pulls.

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https://mbworld.org/forums/c32-amg-c...-engaging.html