You didn't say - but do we assume that this car previously in a major accident? How many airbags were replaced? I've no experience of replacing airbags myself, but your error messages are puzzling...

 

Car was in accident - front right side; driver's airbag and clock spring were replaced with brand new ones. No other airbags opened, or were replaced. I don't know how many people were sitting in the car at that time; it looks that passenger seat was empty and that two peope were sitting in the back??
I don't know if it is normal for all pre-tensioners to activate regardless how many belts were used at the time of accident.

 

I'm no expert, but reading my WIS suggests that there are 2 separate safety systems operating in the SRS, depending on the rate of deceleration.

a) pre-tensioning of seatbelts - with 1 ignition squib (3 stages of operation)

b) operation of airbags - with 2 ignition squibs for driver & front passenger front airbags (for the 2 stages of operation). 1 ignition squib for front/passenger side, and rear passenger side airbags.

i.e, a) will operate on severe braking (only on the seatbelts latched), and a) + b) will operate on severe impact.

Who replaced the airbags? You, your Indy, or MB dealership? If MB, any fault codes should have been successfully reset with STAR diagnosis system.

It looks like the SRS system is managed by the Restraint Systems Control unit (N2/7) that is located beneath the ashtray. I think that this contains the 'deceleration' sensor. This is the unit which triggers the 4 Emergency (compact) Tensioning Retractor units (ETRs) located behind panelling on the B pillars, and behind the rear side panels, - one for each seatbelt.

Each ETR has 3 ignition stages, which are triggered from N2/7 according to the severity of the impact. If the 3rd stage of ignition has been reached, a red pin pops out of the ETR to indicate this condition when examined. Even if all stages did not ignite, the WIS advises renewal of the ETR following a severe accident.

Your existing fault codes could be either ETR squibs that need changing, or wiring that was damaged in the accident. There seems to be no 'common' element here. I assume that your SRS warning light is on?

 

Further thoughts...

1) These 3 error signals are probably from the seats that had seatbelts buckled during the accident - drivers, left rear, right rear. In that case it is most likely that the squibs were triggered, and now need replacing.

2) Just read that there are 2 lateral acceleration sensors in the engine bay for the SRS. These have outputs that go to N2/7.

a) B48/1 driver's side frontal accelerator
b) B48/2 passenger side frontal accelerator
c) These sensors are truly sensitive, see this:

 

Hello guys, if thoose 3 codes (91C3, 9183 9203) are still present (currecnt & stored) that meens the squibs have been activated & the vehicle is going to need thoose ETR's.

Mostar1 here are some pics & if it helps, after you replace them you will have to reset codes again. By the way, I would not trust my life or the life of loved ones to rebuilt or reconditioned safety components. Just my thought.

Here is the info:

Rear ETR's:

Front seat belt:

Red check dot on front seat belt:

 

Thanks guys. I am not mechanic and have very little use of those pics. I used borrowed MB Star computer but codes were current and stored, could not erase them.
By removing seats I saw that I will be able to remove the belts and send them to service. This service is using the original parts and they have many positive feedbacks on eBay. My other option is to take home equity loan and take car to a dealership.

 

SRS Deployment Logic

Here's the document that outlines the operational logic of the SRS in a W204. I suspect that the SRS logic for your car will be very similar. Hence it is likely that your car was in an accident with only the driver on board. The outboard rear seat belt tensioners deploy whenever ANY airbag is deployed.

Once you have replaced the rear outboard seat belts (complete) and drivers seat belt assembly (complete) you will need to go to a MB specialist who can reset your SRS module and clear the ECU codes.

Note: if your outboard rear seat belts extend and retract normally, then they have already been replaced. The deployment of the pretensioner leaves the rear seat belts in a retracted ands locked condition. The driver's seat belt is harder to determine whether it's repaired or not. You will need to have the SRS module reset and see if it raises another error or not.

Hope this helps...

 

Recently purchase CLK55 2005, after accident No airbag deployment.
Replaced drivers seat belt tensioner now have to replace seat belt receiver!
still have codes 91C3,9203, but I dont think any rear passengers but did manually
reset rear head rests.. What do i need to do?

 

Restrain system errors need to be cleared by SD only.

 

My technician said the two rear are the receivers only. The seat belts function normally!
I will be replacing Drivers receiver next already replaced DS tensioner

 

Thanks

It looks like both rear seat belt retractors are fine! But the receivers are Blown! Replacing them with good used ones.. Does anyone know if I can use part number A2098600169 to replace A2098600369 ??? Rear Left!
Thanks