Hi, I'm new to this post my name is Tony. I'm looking for a little help. I have a 2000 C280 Sport and my electronics seem to be getting worse. First, my dash is jumbled and barely ever reads correctly (temp, mileage, trip, time). Also, my radio hardly ever works, but the display will read the track number and disc, it's like it's always on mute. Sometimes I'll be driving and it will just kick on, but it usually decides if it wants to work when I start the car up. My SRS light is also on, but I don't think there's anything wrong with it. Basically, I think it might be the wires that run throughout the car and connect all devices together since I have such an array of problems. If you have any idea what it could be or have encountered this problem yourself, please let me know it would be extremely appreciated. P.S. I have heard some thoguhts that it might be a dirty connection and one plug may not be getting enough OHMs, but that's about it. Thanks.

 

Hi Tony,
This is a tricky one. You are quite possibly correct that it is a poor connection between an ecu module and the area network (connects all the units together) but which one? Have you tried disconnecting and reconnecting the plug to the instrument pack as a long shot?
I believe your best bet is to take the car to a MB dealer and get the BODY codes read. These codes are not the ones that many people can read with a cheap scanner. You need expensive scanner or MB Star equipment.

Get the codes and ask garage to reset computer (small charge). Once you know the codes then you are getting somewhere. This just might solve the problem but if it doesn't please come back with the codes and maybe we can help or at least confirm that the garage diagnosis is plausible.
Since you have many apparent problems with different sensor inputs (yet the car is running fine) it must be a component where all the inputs come together. Quite possible that battery disconnect, jump start etc. has scrambled the instrument pack computer memory and a simple reset will resolve. On the other hand.........

Stuart

 

Sorry this has been taking me a while. Thanks for your help. I disconnected my radio and nothing was unplugged, so I don't know what the problem is with that and why it will not play even though the display works. I got the codes read and it came up with PO151, PO156, and N1112. I think the first two are 02 sensors or related, but I have no idea what N1112 is. As far as the dash goes, I'm going to get it fixed tomorrow at BBA-Reman, I will let you know how that goes. They will hopefully be able to rebuild it and they gave me a price of about 280. I forget how someone said to take the dash out, but I think it involves coat hangers, one on top and one on bottom to hook it out. If anyone knows those codes that would be awesome. Thanks.

 

Hi Tony,
P0151 is an O2 sensor circuit low voltage (Bank 2 Sensor 1)
P0156 is an O2 circuit malfunction (Bank 1 Sensor 2)
Note BOTH banks.
Unfortunately I don't have a definition for N1112. I didn't even realise that there were N codes in use.
U codes would make sense. These mean a network problem.

BBA-Reman specialise in remanufacturing MB (Bosch and the like) components. To do this they obviously understand how the MB networks operate. So I'm sure that they will add additional information on this problem.
HOWEVER, make sure you have hold of your wallet. 280USD is the amount they charge for a new instrument pack. Is this diagnosis correct however! I think not. Does it include installation, coding etc and what if it isn't the pack?

The P codes suggest that their is something wrong with the wiring rather than the O2 sensors. Once again this suggests poor connections. Maybe the P code problem is totally unrelated. Maybe not. need to understand history etc.

These sort of problems are often linked to water ingress into the electronics.

Changing the instrument pack change is a two minute job. Remove (special tool) unplug, replug. The pack then needs to be coded for model type (this takes a little longer. The mileage aspects of the pack won't work unless coded) but you should be able to see whether the new pack has solved problem before coding. Get a price for this option before you start!
I still believe unplugging and inspecting all ECU's and sensor connections (VERY CAREFULLY FOR SIGNS OF CORROSION) is one of the first low cost steps to take.
Changing boxes becomes VERY expensive and often does solve the problem.
Let us know what BBA-Reman say.
Good luck,
Stuart