Lost my pump last weekend while stranded in a lonely country road at dusk...1000 miles away from home!
MB Roadside Assistance had me play with the antenna ring as well to see if it was a DAS problem, but no go.
Towed 80 miles to the nearest MB dealership and they confirmed 0 psi fuel pressure.
Parts for the upgraded fuel filter were on backorder, so I had to settle for just getting the pump replaced (or take another extended week of vacation).
Pulled codes and found the MAS was bad as well (read -40 ambient at startup)...no wonder it's been performing like a pig lately.
Mine had under 57K and there was no warranty or goodwill replacement for the pump. Couple that with the MAS replacement, and I was out $1100!