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Join Date: Jun 2011
Location: Northern CA (SacTown)
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SMG Fault codes help
I have a friend who owns a 2008 M5 (around 50K Mi) and has had a few issues with his SMG. He brought it to a local german indy where he was able to pull a 4F40 (hydraulic unit under-shooting of pressure range) fault. The indy was unable to recreate the problem. However my fried has had a few recurrences of the issue. The car will all of the sudden drop into neutral and will be unable to be placed back in gear with that he obviously receives a red cog. not sure how he gets it back in gear but is usually able to find a gear again then he must park it for 45 min or more in order to return to normal. The indy obviously wants to replace the SMG system. Gives the typical answer of making everything new within the SMG system will eliminate any of those parts as the potential problem with the added benefit of a warranty on those parts. With that said I must add he does not have a warranty on the car so cost is a concern.
He is taking it to Mark over at German Motors for diagnosis today.
My thoughts are that it is either a SMG pressure sensor or his pump going bad. I am under the impression that in the 2008 the pumps are not normally problematic as there were some earlier issues that had been corrected after late 2006. Correct me if I am wrong. I just keep thinking it is a pressure sensor issue.
Is the SMG pressure sensor hard to get to (drop trans)?
Any insight will be helpfull
Thanks in advance guys!
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