Hi, I thought I would bring this saga up to date as I get a bit dissappointed when people don't always post their fix.

I will try to shorten this as best I can but this has only recently been resolved.

The customer wanted me to deal with the vehicle and I kept him informed as work proceeded.

After my initial posting the car was booked in at the local Mercedes dealer for the following week to confirm the ECU fault and replace if necessary as they were the only one's that I knew could program it. By the time the car went there it would not crank over.
They had it for 3 months and replaced the EIS,electronic ignition switch. All ran ok for about 50 miles then warning messages appeared in dash - brake pad wear, coolant level, battery warning light.

It has a smart alternator and the info on Merc WIS says connect Star and follow procedure, so I could not get any useful info on alternator to check it. It was charging max 25A at 13v.

I decided I had reached the point where I had to pass it onto someone with proper Mercedes experience and so it went to a Merc independant.
I informed them of previous history.

They diagnosed SAM,signal aquisition module, faulty, replaced it and alternator and all other dash faults returned to normal.

After they called me to say it was done, the car refused to crank over.......not again!

After some investigation they concluded it was CAN fault and their hunch was engine ECU.
They sent it for testing at their tester of choice and it came back "no fault found".

After extensive engine wiring loom inspection it was found that moving one of the ECU multiplugs about 1mm to one side the car started.
The multiplug was dismantled to check pins - all ok.

We agreed, with the customers ok, to replace the engine ECU.

The car has been fine since then.

____________

Was the original EIS ok and did the engine ECU coincidentally come back to life?

This probably highlights the fact that there is no better test bench than the vehicle itself.

It also shows that the Merc. independant and I were both looking at the same end result but we got there by different means, he with his Star machine and me with my trusty scope.

If only we'd changed the ECU last August!!!!!!

Apologies for long post, Martin.