In addition to the 97 SL320 I have a 97 C280, both use the same system.

This is interesting, 1997 DAS with chip in a key doesn't affect cranking, it shuts off the fuel injectors after 3 seconds _if_ the DAS box does does not see a valid key / ECM does not see a valid CAN message from the DAS box. Older non chip key systems did interrupt the starter of the .

I'd say the non crank was brought about by the general module going down. ( in the right hand under hood computer box, the large purple wire is starter trigger. ) and somehow the DAS box was not completing the chip read / compare / write new code to key.

Very late 97 ( 7-97 I think ) / early 98 had a bunch of modules on the CAN network, the older 97 are more hard wired.