W203 intermittent starting problem...SOLVED


New Member
May 20, 2020
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Your Mercedes
W203 C280 2006
This is less a technical question than a heads up to hopefully save one of you W203 owners some stress.

My C280 recently developed a strange intermittent starting fault where it would randomly leave me stranded by immobilising itself. It would start fine one minute but about 50% of the time the key would turn all the way with all dash lights as normal but no cranking.

Local specialist put it on STAR diagnostics for me but no codes showed up. Both of my keys worked fine and the battery checked out ok.

After hitting google and finding lots of possible issues with faulty EIS modules and dead SAM module I started to panic before having my eureka moment.

Maybe the starter relay is on its way out?

One phone call to local merc dealer, £8 later ITS FIXED. Has not re-occurred in three weeks.

FYI it's relay 'S' in the engine bay compartment and part number A 002 542 92 19.

Hope this saves someone some head scratching.

Mercedes-Benz Servicing, repairs, engine and diagnostics
Wayne Gates - Mercedes-Benz, Unit F3, Phoenix Industrial Estate, Rosslyn Crescent, Harrow, Middlesex, HA1 2SP
Tel: 020 8863 9233
Established for 20 years all vehicles washed and vacuumed.
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