BenzManNow

Howdy all,

I have a newly purchased 2000 C230 and the SRS light was on at the time I purchased the car. The previous owner had the issue diagnosed by the dealership and a single fault code was found for the common problem with the child occupancy sensor in the front passenger seat.

After I purchased the car I took it to my local M-B independent technician who's been working on these cars for over 40 years and he confirmed the diagnosis.

I purchased the occupancy seat sensor from the local M-B dealer and installed it myself. I'm very mechanically inclined and have done lots of work on my cars over the years - so I was comfortable with doing this. As is often suggested, I disconnected the negative cable from the battery before performing the repair. Unfortunately, I had to reconnect the cable and drive the car without the passenger seat for a few days as i couldn't finish the job in one day.

I completed the repair a few days ago and yesterday returned to my mechanic to have him clear the code. Unfortunately, he was not able to do so. When he attached his scanner he now finds additional fault codes (probably from my driving the car without the passenger seat connected to the system).

Now here's the part that's got me (and my mechanic) stumped: When the scanner attempts to clear the codes, it comes back with an error message that says "Unable to communicate with ECU". Why would the scanner be able to communicate with the ECU to read the fault codes, and then later say that it is unable to communicate with the ECU when attempting to clear those codes?!?

I can't complete the state-mandated 'safety inspection' until I get this issue resolved - so I am under some pressure as I had only 10 days from the time of registration to complete the safety inspection - and I'm already beyond that deadline.

Needless to say - any advice or guidance would be GREATLY appreciated.

Thanks in advance.

cm60k

There are a group of modules & sensors that been effective directly to SRS system,

"doors modules/seats sensors/ steering angle sensor/turn sensor/lateral sensor",,

"Unable to communicate with ECU" message, could be from the connector port/pins,

when you plugged the scanner, pins not connect properly, check the port first, or prefer to use STAR/SDS...

ZAYED,,

ptcruiser

Just remove the bulb and no one will be the wiser.

BenzManNow

Believe me, I've already considered that many times. But I have to pass a NY safety inspection...and it won't pass if the idiot light doesn't light up when all the others do at start up (bulb check).

Also - this is safety issue and I don't want to find out, at the wrong time, whether or not my airbags are working or not. I and another family member have both been involved in serious automobile accidents - at different times and in different cars - and I don't believe in taking chances with my life and/or my passenger's.

This issue, for me, is more than a mere bothersome incovenience.

But thanks for the thought anyway.

BenzManNow

Hey Zayed, thanks for the input and the advice. My mechanic happened to call me back after I started this thread and he thinks he knows what's wrong. After giving it much thought over night, he said that he recalled seeing this before and that he has an idea to resolve this issue - which involves using a different scanner and 'resetting' the system. He's going to work on it tomorrow. Keeping my fingers crossed because after this it's off to the stealership - and I can't afford to give them any arms or legs.

Will post the outcome once all the dust settles (and I'm revived from the financial shock).

cm60k

That's good, seems you have a careFUL mechanic..,

pls. keep us posted...

ZAYED,,

ptcruiser

Wow, I guess the NY system is a lot more picky than anywhere I know of.
Your right, safety first, especially when you have already experienced the results of an accident. The Mercedes Star system is incredibly good at pinpointing the problems.
I used an OBD 2 on my car, and I encountered the same reset problems.
I used the Star, and had no problem with the fix and the reset.
Good luck

BenzManNow

PT -
My car is still at my mechanic's shop. He's forwarded the "log" to a company in the UK that he works with that manufactures and publishes the scanner he uses - and the software it runs. I'm hoping that tomorrow he'll have good news for me. I busted my !ss swapping out the child sensor seat and would be not-too-happy to find out that it's the SRS control module.

Tell me, how do you have access to the STAR system? Are you an M-B mechanic or do you know one? Or is this system available for purchase by the consumer?

Do tell - this inquiring mind wants to know.

Thanks for your input. I'm hoping all is going to go well.

Mark

ptcruiser

The Star diagnostic system is more or less exclusive to MB. I am living in Guatemala, and the mechanic I use, when I can't DIY, was a Mercedes mechanic with a dealership.
As Mercedes is always updating their technology, he managed to buy the unit from the dealership when they replaced it.
I am sure that in NY, there must be several Mercedes specialists other than the dealer that may have the equipment.
Sad for you that they charge arms and legs in the US for a 15 minute check.
Here, it's $10.00 US, which is a good thing for me.

BenzManNow

This SRS light issue has been the bane of my existence for the past 7 weeks and I FINALLY got it resolved today.

I successfully changed the child occupancy sensor in the front passenger seat myself and subsequently my mechanic (a Mercedes specialist) couldn't seem to find out why he was unable to reset the system. Even worse, there were actually MORE fault codes after I changed the sensor - leading me to conclude that all I achieved by doing the job myself was that I made yet another expensive tuition payment towards my ongoing mechanical education (will I ever graduate? Probalby not...) Bottom line: I was certain that, in spite of being careful, I still managed to screw things up.

And to add a little more intrigue to the story... more perplexing was the fact that my mechanic could read all the fault codes yet whenever he attempted to clear them he'd get an error message on his scanner that said "Unable to communicate with control module. So there was communication with the module to read the codes yet no communication to clear them. Right. This left both my mechanic and I scratching our collective heads (and simultaneously muttering "oh sh*t").

I left the car with him for two days and finally he was able to clear the codes. He wound up consulting with the company in the U.K. that markets his scanner and the software it runs. They required him to send them some sort of log and which ultimately generated a response that prescribed some sort of reprogramming of the srs module - which reset it.

So the airbag (SRS) light has finally gone out which meant that I was FINALLY able to bring my car for it's long-overdue annual state safety inspection (In the state of NY, it's an automatic failure of the test if the inspection station's scanner reveals any srs fault codes - so I couldn't even "fudge it" by taking out the bulb).

So, to recap - several weeks, lots of sweat and anguish and $420 dollars later - my car's SRS system is finally fixed and, once again, all is right with the world (....for now). And in my opinion, $420 all-in is not bad at all - as far as SRS repairs go anyway (it could have been a LOT worse, no doubt).

I'm especially grateful to my mechanic Horty (Foreign Car Motors, Norwalk CT) - A German gentleman who specializes in German cars (how's that for authenticity). A terrific guy who never gave up and who invested far more time in the repair than he charged me for.

And my thanks to all of you who took the time to responded to my post.

Happy Benzing...

Mark