Thanks for your valuable input. Spring looks fine, but not sure exactly how to diagnose the other potential causes, any help in how to diagnose further is much appreciated. I'll be glad to get these issues (one-by-one) addressed. I understand the neutral safety switch could be the culprit for code 6, but could a sloppy (bad linkage bushings) cause the switch to trigger a code as well, or not likely?

Next issue will be figuring out why the front sits too low, and the ADS (shock) light that illuminates most times.

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Mercedes Fleet:
2004 CL600 Designo Espresso SPORT
2004 S600 Designo Espresso SPORT/Lorinser Pkg.
1999 S320
1988 300TE
1972 280SEL 4.5
Diesel Fleet:
2014 GL350 Blutec
1987 300SDL Blk/Blk 4 place seating #18 head
1987 300SDL Smk Slv/Burgangy #17 head
1986 300SDL Blk Pearl/Palomino #14 head w/ 280K
1984 Lincoln Mark VII Fact BMW Turbo Diesel