How can I tell if it's DAS causing my no start/run condition? - PeachParts Mercedes-Benz Forum

mespe · #1 09-25-2010, 10:35 AM

Been reading a bunch, mainly about DAS (Driver Auth system) what are the symptoms for a 1997 S500 with a bad key, Here's what I've seen. Crank, sometimes (more often not) runs 1-2 seconds. Most often no start at all.

PO told me it was DAS, and I need a new key.

So my questions are.

1) With a bad key, or bad DAS, will the car crank or does DAS defeat the starter motor?
2) Can the car run for 1-2 seconds? Or does DAS defeat the ignition?
3) Can I defeat the DAS, maybe if I has some schematics or paper work I might could figure something out.
4) Are there any indicators for DAS?
5) I think my car has DAS, as the ignition tumbler is recessed around the chrome ring.

mespe · #2 09-26-2010, 10:24 AM

It's looking like my car doesn't even have Driver Authentication system, there's no mention of it in the owners manual. Anyone know for sure?

HZach · #3 09-27-2010, 01:42 PM

According to the wiring diagram you do have DAS: http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1997/S500/SYSTEM%20WIRING%20DIAGRAMS/6413.pdf
The DAS cannot be defeated as far as I know. If the car runs for 1-2 seconds and then dies, it's probably the DAS.
You also have a starter lock-out relay that would prevent the starter from engaging.

Good Luck,

Gilly · #4 09-27-2010, 02:09 PM

ALL 1997 had a DAS system called DAS X. Unauthorized start means no fuel injection. It will crank though. Authorization is checked by a DAS module, N54/1.
From old training manual.

Gilly

mespe · #5 09-27-2010, 06:50 PM

I stopped by the Mercedes dealership and purchased a new "Master Key" This is one without the remote control. If the new key doesn't work, I would like to attempt to somehow by-pass the circuitry inside the ECU. Since the ECU is "married" to the ignition switch, I don't have much to lose.

I would hate to have to but a 4 barrel on this car just to drive it,,,

Gilly · #6 09-27-2010, 07:22 PM

Quote:

Originally Posted by mespe

I would hate to have to but a 4 barrel on this car just to drive it,,,

NOT as much as the CAR would!!

kiwi_bloke_nz · #7 09-27-2010, 08:14 PM

Is DAS related to the K40 relay?

I had an instance in my 1996 E320 where it would just crank, and the lights on the rear view mirror would flash.

Replaced the K40 relay and it was fine.

Gilly · #8 09-28-2010, 07:54 AM

Not sure, I'd have to get access to wiring diagrams to tell what the effect is of a bad K40 relay is on DAS, and even then you'd still have to conpare that to your 140, I'm not even sure if a 140 has a K40 relay. Pretty dicey comparing different years and models to each other on MB.
What I do know is that the 210 (assuming it was a E320) had a different DAS system, it was DAS2, not DASX. UNLESS it was an E420 built before 6/96 (nice, huh?) in which case it was (ready for this?) DAS2a.
Anyways, yes an unauthorized start attempt on a DAS2 car will make the red and green lights flash, BUT they do not do this on your 140! The engine just doesn't start and that's all. To the previous comment on having no starter opertaion if the DAS isn't authorized, this is only true (in 1997) with the 202, all the other cars will crank but not start. Very tricky, very confusing time period.

My own suspicion would be the antenna ring around the ignition switch, these were suspect on various manufacturers, not just Mercedes, I've seen a few bad ones so could possibly be why you don't always get authorization. (EDIT: assuming you get the same effect with different keys. My #1 suspicion would be a bad key, but unlikely you have 2 intermittently bad keys)

The 210 you had did not have this type of system, on that one the DAS was activated and deactivated simply by locking and unlocking the car, either with the remote or the key blade, it didn't matter. If the car was locked, it wouldn't start, if it was unlocked (properly!) it would start. If someone jimmied there way in to the car or broke the window, it would not start.
Gilly

mespe · #9 09-28-2010, 02:05 PM

Just picked up a new $30 "Master" key, and the car fired up first try, sounds nice too, can't wait to get her on the road.