Looks like I have found the problems
Most of the time it would only fault B1241 (low refrigerant) This caused confusion since it was not low.
This time I got the intermittent faults causing the problems B1232 & B1233 these are the freon press sensor and freon temp sensor ....................
So I ordered a rec drier and the 2 sensors I will report back after install.

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88 W124 3.0
96 R129 119eng
06 ML350
98 ML320 sold
02 CLK55 amg