Transmission Problem with 2007 S550, Possible Fixes
I was driving to dinner on night and car felt like it was pinging on the freeway, it did it a few times but eventually made it home safe. Leaned towards it not being an engine issue because car revs fine in neutral or park.
Next day, I was leaving the mall when all of a sudden the car goes into "limp mode" I was stuck in the parking lot because car would not go into any gear. When I put it into R or D it would just rev up and not move at all. Eventualy it would not even rev up even after pressing the gas.
I was able to make it home by power cycling the car (turn off, open/close door, activate alarm, and then restart). After power cycling the car would shift fine for a few seconds and then go into "limp" mode again. I noticed it would usually happen after getting into about 3rd gear.
I go to start it about a week later and car goes into d/p fine when cold, but same thing after a while, limp mode.
Other symptoms: When I first start car up and rev in neutral or park it sounds fine, but after a while when I rev in p/n it has a weird winding noise (electric motor is sound, high pitch). When I power cycle and rev again noise goes away. It also gave me a random P0653 High Voltage Code, but I think this may not be relavant or random, I don't know. Voltage seems fine after scanning with my scanner (between 13.5-14.5V).
I am leaning towards the problem being in the valve body from what I have read, but am kinda leaning towards trying a fluid flush (not hopeful). I have also orded a voltage regulator due to the code I received, but don think this is the problem now. I will change this (since I have ordered already) and then update you guys...
Anyone else have a similar problem? If so what was the fix?
Car gas approx 110k miles and I just purchased it about 2 months ago.







On the 722.6 transmission, there are 65 diagnostic failure codes. I will assume it is similar on yours.
An OBD2 code reader helps but is not optimal. Example, one OBD code (P0700) is displayed for eight unique diagnostic trouble codes (DTC 041 through 052).
The info on the transmission error codes is out there but you'll have to spend some time searching for it.
These are complicated cars and some tests require specialized equipment. You either buy it or you pay someone who has it. You can always post a request to see if someone in your area has the diagnostic system and is willing to come over to your place. Otherwise, flat-bed the car to a shop with the tools.
Best of luck to you.
On the 722.6 transmission, there are 65 diagnostic failure codes. I will assume it is similar on yours.
An OBD2 code reader helps but is not optimal. Example, one OBD code (P0700) is displayed for eight unique diagnostic trouble codes (DTC 041 through 052).
The info on the transmission error codes is out there but you'll have to spend some time searching for it.
These are complicated cars and some tests require specialized equipment. You either buy it or you pay someone who has it. You can always post a request to see if someone in your area has the diagnostic system and is willing to come over to your place. Otherwise, flat-bed the car to a shop with the tools.
Best of luck to you.
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You're getting a bit ahead of yourself jumping to replacing valve bodies without doing the basic diagnosis steps first.


