CLS55 AMG P0638 Throttle Issues
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06 CLS55 AMG
CLS55 AMG P0638 Throttle Issues
Just bought a CLS55 AMG, only about 86k miles on it but plenty of issues since it was sitting for a few years. Major 2 are P0638 and P0600, which are throttle range/performance and internal communication fault. The car will not go over 20MPH and wont hit over 1900 RPM when floored. Replacing the throttle body with a (supposedly) good used one and a brand new one has not solved this and the throttle plate does not move when I step on the gas but RPMS still slightly rise. Any suggestions? Also getting P202E-008 (Throttle Related mentions code P0120), P203E-004 (Unknown relation but mentions posted code P0600), P2316 (No description), P2315 (No description), And P2314 (No description). A few other things on the dash like oil display malfunction, SRS malfunction, and ESP malfunction. Anything that can point me in the right direction is greatly appreciated!
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2006 CLS55 AMG, 2005 SLK 350 AMG
Just bought a CLS55 AMG, only about 86k miles on it but plenty of issues since it was sitting for a few years. Major 2 are P0638 and P0600, which are throttle range/performance and internal communication fault. The car will not go over 20MPH and wont hit over 1900 RPM when floored. Replacing the throttle body with a (supposedly) good used one and a brand new one has not solved this and the throttle plate does not move when I step on the gas but RPMS still slightly rise. Any suggestions? Also getting P202E-008 (Throttle Related mentions code P0120), P203E-004 (Unknown relation but mentions posted code P0600), P2316 (No description), P2315 (No description), And P2314 (No description). A few other things on the dash like oil display malfunction, SRS malfunction, and ESP malfunction. Anything that can point me in the right direction is greatly appreciated!
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Junior Member
Joined: May 2025
Posts: 38
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06 CLS55 AMG
Congrtas on your recent buy. Hopefully, with all of these issues the price was very right. In case you are not aware, the C219 CLS55 is - simply, a reskinned W211 E55. Since there were many, many more of those built there is a lot more traffic on that forum page. Drop in there and post your question and you will get a lot more eye ***** looking at it and more responses. See you over there and welcome to the forum. https://mbworld.org/forums/w211-amg-81/
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2006 CLS55 AMG, 2005 SLK 350 AMG
If you are doing the work yourself then it is strongly recommended to get the MB Star diagnostic system. If you are having a shop do the repairs, then you will pay everything you saved.
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2006 CLS55 AMG, 2005 SLK 350 AMG
One other item. In addition to the throttle body there is a second by-pass throttle body under the back of the SC. Can't really see it from above and everything in place. The electrical connections of the two throttle bodies look the same. If the cables to the connections get swapped nothing works correctly. In your situation i may be worth chasing that possibility down.
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06 CLS55 AMG
I cant seem to find any straightforward STAR diagnostic system explanation or availability, but im really wanting to go down that road as I have not had a shop work on anything ive owned before (Besides of course tires or using their alignment rack) and I dont plan to now. Is that electrical connection under the supercharger or is it somewhere else? I noticed that bypass when replacing the main TB but the electrical was just that 1 connector that I saw that has around 1 foot of wiring until it jumps to another that leads below the supercharger.
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Joined: Jun 2020
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2006 CLS55 AMG, 2005 SLK 350 AMG
I cant seem to find any straightforward STAR diagnostic system explanation or availability, but im really wanting to go down that road as I have not had a shop work on anything ive owned before (Besides of course tires or using their alignment rack) and I dont plan to now. Is that electrical connection under the supercharger or is it somewhere else? I noticed that bypass when replacing the main TB but the electrical was just that 1 connector that I saw that has around 1 foot of wiring until it jumps to another that leads below the supercharger.
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From: Central Pennsylvania
1994 S420 RIP (2/8/13), 06 CLS55, 02 ML55, 94 TT Supra, 89 Maserati 228, 911 Porsche Carerra
It would seem that you have gone into limp mode. You’ll need a Star diagnostic to clear the code and get it out of limp mode. I’m unsure of other’s but I know the Star diagnostic is the key. Mhad typical transmission issues and after fixing I still had to clear the code to get it out of limp mode. Good luck.
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