W211 facelift red battery visit workshop warning

[Damion_n]

I purchased a facelift W211 e200 kompressor. I got the famous battery visit workshop warning error. I immediately purchased a brand new Bosch alternator thinking it was the problem but to no avail. I purchased a used but fully functional rear Sam and the rear link fuse box control module, after installing to my surprise that didn’t remedy the problem. I decided to try one more solution so I purchased a brand new battery for the car but that still didn’t remedy the problem. I am out of luck plus I don’t want to throw anymore money at it. I have read countless threads on various US and U.K. sites but they seem to focus on the pre-facelift model. I am seeking anyone here that can help me narrow down this problem and once and for all get rid of this problem. I must also note I don’t seem to loose any function like the convenience function or radio. Any help I get would be greatly appreciated.

 

[Blobcat]

Hello and welcome

Have you had the error codes read with a Mercedes specific code reader?

 

[Damion_n]

I scanned it but nothing out of the ordinary came up. I cleared the codes and nothing came back up. I will check it again and report back to you blobcat. Thanks for taking the time to help me out.

 

[Blobcat]

I didn't think the facelift W211 had a second convenience battery but battery is where I'd be looking - whats the voltage when the car is off?

 

[Damion_n]

The facelift only have one battery in the trunk, None in the front of the car. I didn’t check the battery when the car is not started however while the car is on it have a voltage between 12.5-12.8 volts. That was the reading I got before I changed the alternator but after changing the alternator the new one gave the same reading. Hence the reason I say I am out of ideas.

 

[Blobcat]

Should be ~14V with alternator running and 12.6-12.8 with the car off

 

[Damion_n]

I figured that much but while the car is running it gives 12.5-12.8 volts. I know it’s under charging but two alternators can’t give you the same reading unless something is breaking down the volts before it reaches the battery. That is what we need to investigate

 

[Steve@Avantgarde]

Why do peple throw upteen parts at cars in the mere hope they will fix it, based on pure speculation and then get upset and dont want to spend any more money with a proffesional who knows how to fix it? Happens so much on here. Anyway.

The vehicle has a battery control module that looks at and measures both batteries. If there is an auxillary battery fault for example, the huge drain into that it will cause the issues you have.

A scan with a STAR machine will tell you what the battery ECU is doing and what other systems are being affected by this fault. You will then be able to do some specific tests to fix it.

 

[Damion_n]

To be quite honest Steve@avantgarde if you read the post you will notice it’s not a pre model but rather the facelift model with only one battery. Speaking with ignorance is not solving the problem. What you spoke about in my opinion is a car equipped with two battery however my car only have one battery in the trunk. Now that I have said that, the question i want to ask is my car equipped with a battery control module? I know on the pre model it’s located in the trunk of the car however in my car I can’t seem to find it leading me to believe I might be looking in the wrong place or it was never installed in my car. If you know the location with supporting literature can you upload it so I can have a look at it. Another point I should note I noticed there is a sensor attached to the negative battery terminal. What’s the function of the sensor?? Could it be causing my problem. P.S. it’s not that I can’t afford to throw parts at my car or upset to spend anymore money at it. The parts I spent the money on are wearable parts over time. I have a few extra parts that can come in handy in the future. I don’t look at it as money wasted. Now I have said that forums were created to form a network for car enthusiast like you and me to share our knowledge on owning and up keeping our cars as we have a passion for owing them. I look forward to hearing from you with positive information with regards to my problem.

 

[PovertySpec]

This escalted quickly....

 

[Damion_n]

Absolutely not PovertySpec there is nothing to escalate. We are here to help each other and share ideas.

 

[Srdl]

I think Steve has already given you the best advice which is to plug the car into the Mercedes scanner system (Star) and, once you have a clear idea of what is causing the problem, then start replacing faulty bits.

 

[Damion_n]

Ok no problem. I will let the star diagnostic see what’s going on. I did scan the vehicle using an Autel diagnostic machine but nothing came up out of the ordinary. I cleared the codes but nothing reappear hence the reason I say I am clueless.

 

[Srdl]

Where are you based? We may be able to recommend someone local who has Star.

 

[Damion_n]

I have star plus I have the autel diagnostic scanner as well. I am scanning with star at the moment performing a quick test. When I am finish I will post the results for you all to have a look.

 

[Damion_n]

I scanned the car. Here are the results. If you all need ask me anything else please don’t hesitate to ask me. I have a developer mode c3 so I can redo a scan anytime.

 

[Damion_n]

The event memory concerning the body control module cannot be erased however it’s not showing up as an error code. Secondly the error codes in the San unit are related to a pair of after market headlights I installed that cannot connect to my bi xenon headlights original harness. That is being removed in the coming week.

 

[Damion_n]

Can anyone assist with the star reading to narrow down my problem