After replacing the passenger rear wheel bearing, had to diagnose a no start. Glad I have a STAR. Isolated to an ignition issue. No previous running issues, so started with checking engine ground. A temporary ground quickly had the engine purring away.
A replacement engine ground is about $23 from M-B. The replacement cable appears to be 2 AWG and the OE feels like 8 AWG at best.
I will have to get under the car to access where the cable attaches to the engine and I suspect the plastic guard with have to be removed to get to the bolt. Replacing the ground on the 450 was much easier.
Making use of the new cable, an alternate bolt location on the top of the engine and jumper cables, I have a temporary solution for a couple of days.
Also the secondary air injection pump is in the way to get at the chassis mounting point. So the non functional pump may get the old heave ho.