W203 one problem leads to another

[philsas]

Definitely a new and bemused new member.....
i have a w203 C180 registered 2/03. I have had 4 trouble-free years motoring until recently. Just a few weeks ago i had a battery/alternator undervoltage warning - this disappeared after 10 mins driving. The advice that i had was that because of underuse (3000 miles per year) the battery had probably lost some charge.However a few days later the diagnostic lamp came on and stayed on !
I took the car to my local garage (non MB) who advised that there were also a number of other minor codes - he reset (£45) and advised that "wait and see" was the best approach. All well and good for 3 weeks until the SRS light came and and stayed on. I have carried out the checks recommended on this site but this is still a puzzle. However I then began to have difficulty with the steeing wheel button functions - this problem was intermittent at first but has since become permanent, not a peep.
Is there a genius out there who can zero in on the problem ??
(and what is a SAM .... and indie.... never heard these terms before!)
many many many thanks....

 

[jaymanek]

id say you need to get plugged back in, probably unrelated.

Indie - Independent Garage
SAM - Signal Aquisition Module.

 

[markjay]

Yep, you need to get the codes read, and next time before the garage erases them, get a list and post it here for some advice.

If you think the battery is the problem, have it replaced...

SRS could be something (relatively) simple, e.g. faulty passenger seat ocumpancy sensor, but you need to know the actual codes to be sure.

Also... where in the UK are you?

 

[markjay]

And... you may want to invest in a code reader, rather than paying £45 to the garage every time.

I have this one:

Autel

It costs around £170, but it reads and erases fault codes in the engine/transmission and other modules e.g. ABS, SRS, etc.

With this kit, you can read the codes yourself and get some idea what you are in for before going to the garage.

 

[trainer]

As a matter of interest does the horn work? If not then the steering wheel button issues may be to do with the clock spring.

 

[Privatedoc]

SRS problem, I had this........turned out to be a seat occupancy sensor in the passenger seat....not to tricky to replace apparently but as I'm under approved used warranty, had the dealer do it......tells me he's done a few w203 seat sensors...fragile wires in sensor apparently.

 

[philsas]

thanks for the prompt replies !
I actually live in Sale, just outside manchester.
Unfortunately the horn does not work either - is this clock spring easy to correct ?
Will get plugged in this week to see what the SRS problem is - although when I have a passenger who does not fasten seat belt the audio warning still sounds - could it still be the passenger seat sensor ??

 

[Stratman]

If you have a passenger who doesn't belt up the alarm is supposed to sound.

Having just re-read your post I misunderstood it the first time.

A thousand apologies.

 

[markjay]

If you have a passenger who doesn't belt up the alarm is supposed to sound.

I think what he is trying to say is that if the belt alarm and seat occupancy sensor were one and the same, then if the seat occupancy sensor was faulty the belt alarm wouldn't have worked either.... i.e. casting doubt of the seat occumpancy being the culprit.

 

[markjay]

thanks for the prompt replies !
I actually live in Sale, just outside manchester.
Unfortunately the horn does not work either - is this clock spring easy to correct ?
Will get plugged in this week to see what the SRS problem is - although when I have a passenger who does not fasten seat belt the audio warning still sounds - could it still be the passenger seat sensor ??

This will give you some idea what's involved in replacing the seat occupancy sensor (it's for W210, but very similar to the W203):

Occupancy Sensor Repair W210 - Mercedes Benz Guide and Repair Wiki

 

[markjay]

But before speculating any further, it is important to get the codes read...

 

[brian c200]

welcome to forum phil live in m/c myself had mercs for 7 years now try mastertech assist droylsden indie merc specs 40 years exp[ tommy ,craig] will be able to read codes {star machine} hope this helps.

 

[philsas]

and there's more...Today the diagnostic warning lamp came on! Haven't had a chance to take this in to get codes read, but is there a chance that all these problems are down to a battery that is not holding its charge ??

 

[philsas]

and there's more.
I have just remembered that during service in June (indie) the indicator stalk was replaced. How likely is it that something was disturbed to bring up an SRS warning, and at the same time stop the sterring wheel buttons from working. Any advice would be appreciated before I take the car in for codes to be read !!!