And now after 70 mph it goes into limp mode ..

its 2011 ML 550 4matic … the car came to me after the first shop replaced the conductor plate !


I have graphed all abs sensors , and the speed sensor and there is no erratic signal showing …
No abs codes only other code is Dme code showing the speed sensor telling the TCM implausible signal ! I will
post this next ! The car only has 44k miles on it , t there is no slipping or feeling of transmission pressure making the clutch packs slip! Not until u hit 70mph the car goes straight to that PO730
I think we either have a defective conductor plate or bad programming…, thank u so much

 

 

This could be an old fashioned diagnosis rather than an electrical one. Check and make sure all your drive shafts/unis are in good health. It could be a vibration at speed that throws out the equation between speed sesnors and the transmission. A long shot, but you never know.

Have you viewed live data at 70mph when the problem occurs? Speed sensors can create ******* problems but are easy fixes and relatively cheap.

 

sounds like erratic sensors on the conductor board??