Originally Posted by bieber

Thanks guys, it has all worked out well, no P0410 codes after 1000 miles on my repaired RCM. This car is my daily driver, your help gets me to work.

I bought a few relays per your information.

I used the the "W210" (inexpensive) junkyard RCM as a backup during repair of my original RCM without issues.

An aerospace spark-chaser friend changed the air pump relay on my original RCM and re-soldered the "mystery no start' connections (they looked bad under magnification).

I then re-installed my now "repaired" orgininal RCM, stowed the junkyard item as a backup with the spare CPS in the box 'O stuff I keep in the car, and it all seems to be working well.