I have a 2000 c230, and also a mercedes star diagnosis system. The DAS unit will not read my car. I get a message stating the possible errors when trying to connect. The cables are loose and maybe circuit 30 and or 31 is faulty. I traced the pins 30 and 31 from the 38 pins socket das connection to some relays behind the fuses in the engine area. I have the part numbers of the relays: 0025421419(yellow), 0025420319(black), and 0025421119(green). I noticed that when number 0025421119 (green) is shaken it make a rattling noise. I dont know, do I need new relays? Can anyone help me with this problem so I can use my star diagnosis on my car. Thanks!!

where are connecting the tester? under the hood or under the dash.

It should be hooked to the 38 pin in all cases that there is one such as this car.

Try talking to the EIS. It will talk with the key off verifying whether terminal 15 is an issue. All the DAS is looking for is 31, 30, 15 and the diagnostic line specific to the controller on that model. Be sure you identify the car properly.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

I tried connecting the system both though the 38pin under hood, and obd under the dash. And the same message appears. I hope I am following the steps properly: Car, C class, the onto c230. And that is when the message appears. could it possibly be the circuit relay behind the fuses under the hood? Thanks!

It has to be connected to the 38 pin. It will not work in any fashion on the OBDII connector.

What does the error message state? When there is no communications the SDS software will direct you to the issues necessary to communications. The SDS will communicate if it has permanant hot (battery voltage), ground, switched hot (term 15) and connection to the diagnostic link to the controller. It can be done manually with the universal cable by just attaching those four wires. Verify those four pins in the 38 pin connector. If they aren't working use the wiring diagram to locate the problem.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

its states the voltage at (circuit 30 and or 31 is faulty), or diagnosic link to multiplexer is not connected, and etc. I went back to the pin number 30 and turns out that I was following the wrong wire to the relays. So I am going to try and find where the wire leads to. I know that in pin number 30 the wire is yellow. I am not sure if that can help. Thanks!!

have you tried the sds on another vehicle?

yes, I know that would be the first thing to try, but it works on other models. does anyone know where the pin 30 yellow wire runs to. I pulled the carpet up on the passenger side and it must run to something on the other side. Thanks!

have been looking on my benz wis and pins number 30 and 31 are 30(airbag) and 31 (Remote locking system). Maybe as I am looking now it says: pins 1 and 3 are circuit 30 and 31. That must be where it is shorting....

I fixed it. It turns out that a 7.5 fuse was blow and the fuse was next to the diagnostic socket near the computer module. well, thanks for everyone who helped!