Fuel tank sending units are a problem on MOST newer cars! NOT just MB's. That COULD be due to the additives that the gas companies are using to reduce emissions!

AS far as the check engine goes, ANYONE with an ODB2 scanner should be able to find the problem (code).

ONLY! ON the 1998 SLK there is a alternator by-pass relay that can cause the car not to charge. THAT relay was designed to cut off the alternator in case of an accident! THEY didn't work well & MB discontinued that design before the 1999's came out.

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MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator