Brian Darby

I need help here please. I have an 04 CL K320 convertible with 57,000 original miles, for the past two years the SRS light has been on and they told me that the module needs to be replaced because it is burned in the prom in the module and can't be cleared. We want to sell the vehicle due to high repair costs and we haven't found a shop that's reasonable locally. They tell us these modules have to be programmed by Mercedes, but I see them for sale used on the Internet. I have been a mechanic my whole life and there's nothing I can't fix, but I'm a little stumped on this one. I've heard it could be the occupant sensor switch I don't know what to believe. I love to keep the car but I can't afford $1700 to have this fixed, please help

Rudeney

Get the codes pulled from the SRS module. You won't be able to do this with a generic OBDII scanner - you'll need a specialized tool that reads MBZ's proprietary systems. The dealer's SDS will do it, but you might check out iCarsoft i980. Once we know the codes, we can better help. If the module does need to be replaced, it is possible to install a used one. If it comes from an identical car - same model, year, and exact options - then it's plug and play. If not, then it will need coding, which will require SDS.

Brian Darby

I will do that, fyi they told me there was over 1500 faults and it could not be reset. Should I ask the shop for the codes? Would that be easier because I can get a copy of it

Rudeney

There aren't 1500 codes for the whole system:

http://benzbits.com/DTC/SRS%20(B%20codes).pdf

Given your other issues, it might be worth investing the ~$130 to get iCarsoft i980 and pull codes for yourself.

Brian Darby

I will do it, my apologies, I did not mean 1500 separate codes, I mean the system kept tripping one or two codes for up to 1500 times, and they tried to clear the system but could not due to so many instances.

Rudeney

Ah, that makes more sense!

Brian Darby

Here are the airbag codes which will not clear
B2D92
B1003
B1058
B1055
B1076

Rudeney

B2D92 Control unit N2/7 (Restraint systems control unit) is defective.

= The SRS control module is defective an must be replaced. Neither this error nor any others can be erased when the module is defective.

Brian Darby

Well I can't afford a new one so how do I go about finding a used one?
I did get the information with the reader about the module for the airbags

Rudeney

You can install a used one. Get one that is the exact same part number as yours from the exact same vehicle with the exact same options. Otherwise, you'll need SDS to code it (not "SCN" coding, just basic adaptations). It's kind of a PITA to install - you have to remove the entire center console.

JYO

Hi there I am getting error code :

9084 - N2/7 (restraint systems control unit) coding is faulty

can you tell me what that indicates?
I also have codes 902C at 902D.

902D showed up after I replaced the seat occupancy sensor which I think is normal to occur once it’s unplugged and plugged back in however I’m not sure that was the source of the original problem. Thx