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ATA & IR Modules

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1995 SL500 - Do replacement units need to be programmed? My iCarSoft scanner sees the ATA module but can't read it and my IR currently does not work on any door, no lights.
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2002 MB S430 W220, 1995 SL500 R129
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65 Posts
Discussion Starter · #2 ·
I found one reference about the ATA not having CAN functions, but not certain. Still nothing about programming or its relation to IR module and if that needs to be programmed as well. I bought a module from ebay to give it a shot. The part numbers are the same 140 820 57 26 [12] & 352 177 but there is a faint "94Wxx" code beneath 352 177 that is different on the units I can find for sale - the one in my car is a "94W34". Here's an example from the web:
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Outstanding Contributor
R129 500 SL 1991
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2,210 Posts
Assuming your car is MY 1995, I believe it would have DAS1a authorisation. I assume you point the IR at the doors, you don’t have a receiver on the rear view mirror, correct?

The receiver on the door sends the signal to the infrared remote central locking (IRCL) control unit, which decodes the signal, and if the code is correct, it actuates the anti theft alarm (ATA) and PSE controller unit, which pneumatically activates the central locking (CL).

The receivers, control units and actuators (PSE) are hard wired on a MY’95, so they do not operate like a more modern faster CAN BUS system.

You say your IR does not work on any door, but you can start the engine? Please confirm. Unlocking the door locks with the key DOES NOT activate/deactivate the ATA. So I assume your ATA is currently deactivated.

From the start of 1994 all R129s had an immobiliser as standard. Because these older systems can be finicky, some BW members just don’t use the convenience feature anymore, they just use the key to avoid activating the ATA and not being able to start their engine. If you are not sure what you’re doing, don’t do anything that might inadvertently activate the ATA, just in case you cannot deactivate it.

The IRCL can be resynced by pressing the IR at a door/trunk receiver, then switching ignition on within 30 secs. AFAIK a replacement IRCL does not need to be reprogrammed other than resyncing.
 

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2002 MB S430 W220, 1995 SL500 R129
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65 Posts
Discussion Starter · #4 ·
Hi Rob,

Thanks for this great info.

No receiver on the mirror, it is a 1995 SL500.

No IR, no green or red lights are functioning on any door or trunk but I can start the engine.

Wife went into labor last Thursday and we just got discharged yesterday with a brand new baby girl. I *should have the time to fiddle with it this weekend. Will follow up.
 
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