Jim,

Check to see if your chrome ring(the coil) on the ignition is not pinched or open from the connector on the DAS box behind the cluster. You pinch, or cut that wire, and you are TOAST....

The signal is not picked-up

Martin

As noted in the OP, I checked the transponder ring by unplugging it at the DAS module, and verifying continuity via an ohm check. The transponder ring showed 0 ohms resistance. That suggests it's good, right?

Jim

__________________
14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

Well, it's gotten interesting.

We picked up a parts W140, one that we verified started and ran (not move, the tranny is bad).
Recall the good car is throwing a P1570 code, indicating a communication problem between the DAS and the ECM.
Swapped out the ECM, DAS and set up a loose transponder ring with the parts car RFID chip key next to it.

Still got the start error.

Now it gets interesting. We took the ECM, DAS and transponder coil and key from the "good" car and swapped them into the parts car. Guess what? The parts car started. Also worked fine with the new dealer key.
Seems like the next area to look at is wiring continuity.
The aftermarket clone SDS system I'm using has the wiring diagrams on it, but I have not been successful in finding them yet.
Think I need to sit in a chair, with an adult beverage and play with the system for a while......

Frustrated, but at least I don't need to drive the car tomorrow. Been driving the BMW Z3 in lieu of the S500, kinda getting used to it, it's a fun little go cart. Might be nice enough next week to consider putting the top down for the commute.



Jim

__________________
14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles