Airbag light on: Internal control-unit fault - replacement modules s0180 error


May 19, 2019
After water penetration I got the dreaded red airbag light on.

Insta+ reported "93D7 ACSM: Internal control-unit fault".

After installing an identical replacement Insta+ reported "S0180 No communication possible with: Safety module/ restraint system".

Assuming the replacement module was faulty, I installed another identical one , only to have Insta+ report "S0180 No communication possible with: Safety module/ restraint system" again.

I reinstalled the original module and Insta+ reported "93D7 ACSM: Internal control-unit fault".

So, another replacement sourced and installed only for Insta+ to report "S0180 No communication possible with: Safety module/ restraint system" again!

I find it hard to believe that I have received 3x replacement control units each with the same fault, albeit provided by the supplier, however by re-installing the original unit and re-confirming the original fault that is what the evidence implies.

Anybody had this experience or any ideas what could be going on?


Zorg Expert (II)
British Zeds
Dec 31, 2013
Torksey Lock,Lincoln, England
Model of Z
E89 Z4 23i Auto
I can only think that you have to get the "new" module coded to your car.



Zorg Guru (IV)
British Zeds
Nov 25, 2012
Newport, South Wales,UK
Model of Z
Z3 M43 1.8 (1999) and Z4 E85 2.5 (2003)
I feel your pain, had a look at another members project car the other day that has the airbag light on. Scan with bmw scanner revealed the dreaded F0 code internal fault control unit plus both belt tensioners and the occupancy sensor codes. It won’t allow any codes to be cleared. The current module is a replacement for what was in the car when he got it, same part number he ditched the original so that’s lost. However he has another module same part number going to fit that and scan that one, will have to check if it’s going to need coding to the car when we next plug it in. Meanwhile he will be cracking on with his sill refurb and fitting the new otters. From my research the F0 code locks the module up and would need specialist attention to repair and reset, have been looking at crash who do this for circa £70. Will see what the second replacement performs before sending one away for repair and reset.