How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Stan Your Own Question
Stan, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3526
Experience:  Technical support engineer
Type Your Mercedes Question Here...
Stan is online now

I am having starting problems with a 04 merc S211 320 cdi

Customer Question

I am having starting problems with a 04 merc S211 320 cdi estate.
The car would only start with a jump. Now wont start at all. Batteries have been fully charged and load tested. The voltage at the alternator once running is 13.6v both batteries and alternator are new, although fitted before I started work on the car. Some warnings appear on the dash after a few second of running - convenience feartures stopped and the red battery sign. they generally went after a few minutes and the car would run fine until switched off, where it would need jumping again.
I have Star and have scanned the car. there are no faults showing up in the BCM, I have done a BCM reset to be sure and no codes come up. I did find some codes in the battery relay and that showed as having some sticking contacts, so it has been replaced. Still wont start and still has the warnings coming up on the dash
Scanning the front SAM there is fault code - 9081 signal cable Terminal 61 open circuit. (terminal 61 implausible).
Star gives various guided tests for trouble shooting but one involves starting the car, which I cant do. The only test I can do is to check the signal cable from connection B1 pin 2 at front SAM to pin 1 at G2 alternator connection.
This is where I get confused. The cable at B1 pin2 is blue and yellow but there is no blue and yellow cable at the G2, at either pin, so I cant get anything at the G2 Plug. However in contradiction to Star - B1 pin 1 (blue and white) tests for continuity at G2 as there is a blue and white cable there.
My first question is - Am I supposed to get continuity at the alternator between B1 pin2 and the blue cable at G2 pin1 as well as continuity between B1 pin1 and the blue and white cable at G2, I assume this should be pin2 at G2 the alternator?
Does the blue and yellow cable at the B1 pin2 go to another component, which is why the colour of the cable changes at G2 plug, if so where is it and could it be at least partially causing the issue?
I have also tested the fuse f56 in the wiring loom between the starter motor and the alternator. When I go into the guided test for this there is fault - 9084 component f56 Starter alternator fuse is faulty. I have removed it visually inspected, continuity tested and resistance tested (0.3 ohms), all is ok.
I have gone through guided tests on the SAM and I am not getting resistance readings with in parameters stated in Star on at least one of the tests between fuse contact. So, I am of the conclusion that the SAM is faulty.
Before I go a head and buy a new one I just wanted to clarify the position regarding the cables to the alternator and check that no other component is between it and the SAM that could be causing these issues?
Submitted: 2 years ago.
Category: Mercedes
Expert:  Shantal-Mod replied 2 years ago.
I'm Shantal and I'm a moderator for this topic.
I've been working hard to find a Professional to assist you with your question, but sometimes finding the right Professional can take a little longer than expected.
I was checking to see if you had already found your answer or if you still need assistance from one of the Professionals.
Please let me know if you wish to continue waiting or if you would like for us to close your question?
Thank you,
Customer: replied 2 years ago.

Hi Shantal,

Thank you for coming back to me. I have ordered a new front SAM as I am fairly sure it is part of the problem, however I would still like confirmation from someone regarding the Terminal 61 tests that are outlined in the Mercedes guided tests in Mercedes Star diagnostic system. My results are not those described in the tests and those that I have seen reported on some forums.

I understand that my question may be long winded and complicated but the issues I am having with the car, whilst appearing to be common symptoms with this particular model of car are not quite equating to any answers I have currently found and that includes my local Mercedes main dealer.

I look forward to hearing from yourself or a technician/expert in due course.

Thanks Paul

Expert:  Stan replied 2 years ago.
Hello Paul,

The car should start if there is no alternator connected to the vehicle, so missing 61 should not cause anything besides charging error in the cluster.
There are different regulators used on the vehicles and several wiring diagrams. Some have the 61 output to SAM, some LIN signal from voltage regulator to the engine control unit.

It is important to know if the engine is cranked by the starter, or the starter is also inoperative to help you further.
Also, the VIN would help me to find the correct wiring diagrams to assist yoou further