Ive got a ML 3.2 diesel 2007, that went into Limp Mode after towing a 1ton trailer, Check Engine light came on and wouldn't rev over 2k rpm. after a mechanic put a scan tool on it, it came up as faulty (or stuck) SCV.
Next day it was ok at first, check engine light not on, but CEL and Limp mode happened again while towing, after researching this forum and on the net, I sourced a new OEM SCV from Repco and fitted it, still had the problem.
After an auto sparky put the scan tool on again it was still showing Stuck SCV, he did a fuel pressure test and said it was about a third of what it should be from memory it was reading 11,000PSI. He suggested changing the fuel filter first which i did, it was filthy inside the white sensor on the bottom of the filter, (might have been 25k or more since filter changed ).
Still got the Limp mode problem, what would my next step be?, take it to a dealer for this MUTT3 recalibration thing of the ECU/SCV I read about?
Put 300ml of Castrol Activ FC rated 2T in a full tank?, but cant really drive it properly in Limp Mode?