We recently had this code on one of our oldest customers cars.

During testing everything checked out. In reading the freeze frame info on the code the temp of the fuel was over 40deg C at the time of fault, BUT the engine temp was something like 18 deg C. From all the other values it was apparent that the event happened on a heat soaked engine. One who had been driven hard then sat 20minutes then was restarted. This was confirmed by the customer on two events.

We would have replaced the engine temp sensor, but he was a thousand miles from the end of his starmark warrantee, so we informed him of the remote possibility that this also could be a control unit problem. He has a good relationship with a distant MB dealer and he took it there and they replace both sensors and the controller.

The reason I point this out is that I am relatively certain that the real problem was the engine temp sensor. The normal range of accepted fuel temps ends at 40degC I think, but it is entirely possible and very likely that in climates like Floridas that a hot soaking motor will heat the fuel that hot. I would presume an engine temp similarly situated would excuse it. it our case the fuel temp and intake air temp planely showed the heated compartment and the engine temp was lower than it had been since last winter. Just a thought.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician