Was just driving home casually through the neighborhood last night and got a CEL. Took it to my indie shop for diagnostic who pulled the code and got a P176D09 code for "The electric additional compressor has a malfunction. There is a component fault."

I have a CPO warranty still so took to the dealer (unfortunately with the CEL cleared) and the CEL did not come back on the drive. They are going to try diagnosing without the CEL and pulling the logs to see it along with my pics with the code. I'm optimistic that it's going to be covered under warranty if it's something with the electric compressor (supercharger?). Tried poking around online and have not seen any other reports of similar so curious if other E53 or M256 people have had this before so started a thread.

 

Turned out to be the A/C compressor. CPO warranty taking care of it.

 

Several reports for CEL with '53's and. 450's for various reasons ... frustrating

https://mbworld.org/forums/e-class-w...ine-light.html

https://mbworld.org/forums/e-class-w...epeatedly.html

 

yeah i mean not surprised on my car given it's a few years old. **** happens

 

final update: was not the AC compressor the SA misspoke. replaced 256-090-60-00 all under CPO warranty

would have been $4-5k without. definitely looking into extended warranty now

 

I have the same problem. Did you get any more details on what exactly the fault was. From what I have read online it mentions it could be a fault in the open circuit. 5k Sounds like they replaced the whole electrical supercharger.

 

yes they tested it, got code P176D09

no visual issues present, so they did a manual actuation test which it did not respond to. then tested the voltage check which was okay. tested the resistance at 90 ohms which indicated an internal fault. to my understanding of electric motors that sounds like there was most likely a breakdown in the windings and it failed open, which won't allow the motor to function. they replaced the whole part. it's quite a lot of labor to get to the unit. i'm not aware of the specific root cause of the failure but i'm guessing the heat or whatever caused some winding somewhere to short and fail

 

yeah it’s the same code I’ve got. Makes sense. I appreciate the reply as I was looking everywhere for information on this. I’m dreading the replacement costs

 

yeah that's a bummer

i'm not sure if it's too hard to tackle on your own, the part they replaced for me is only around $1000: https://www.mbpartsgiant.com/genuine...sor~2560906000

an indie shop near me originally quoted me ~$4k but i was able to get it covered under CPO so had the dealer do it

 

Hey there!
I have the same error code on my 2021 E53 AMG Coupé. My car does not have warranty anymore sadly.
I also have a weird , loud whistling noise under heavy acceleration usually above 5k RPM. Had this sound for 4 months now but theres absolutely no power loss.
I have a good mechanic who's going to look into it next week. Might be a leak from the compressor to the turbo... not sure. I really hope the part does not need to be replaced...
Did you hear any weird sounds while the error code was there?

Thank you in advance!

 

i don't remember any symptoms at all. no sounds, no loss of power, nothing

post what the outcome is once you know, will help others in the future