bnz616

Has anybody every gotten the "Light Sensor Visit Workshop" error? I got it about a week ago and it came up again today. Is it referring to the light sensor that senses if its dark outside to set the nav display to dark, turn on fogs when you unlock the car, turn on headlights on AUTO mode, etc? Everything seems to be working fine. Anything that could be causing this error to come up? I also keep getting the "Left License Plate Light" error but everything is fine.

Thanks.

benzmodz

That last error you mentioned is a common fault in the wiring. There is a bulletin about it.

Seems that your daylight sensor is causing error codes.

bnz616

So the license plate light is a common fault in wiring? Or is the light sensor a common problem?

Anything I can do to fix either one? I'm out of warranty and don't really want to drop off the car for day since I won't be able to get around. They don't seem to be causing any problems, but warnings popping up once in awhile is annoying.

Thanks.

glomar83

i also got the license plate warning. i haven't checked to see if the bulb is actually out though. also, does anybody know how to change the clock on the instrument cluster. mine has been an hour ahead since daylight savings.

bnz616

Since the "Light Sensor Visit Workshop" error came on, I noticed things aren't really right. When I start the car, it seems to take a little more work to start up, the instrument cluster dims quite a bit and flickers when I turn the key to start the car up. An ESP error message came up twice also with the Sensor Light error. The transmission got stuck a few times, it jerked into drive or reverse, and the W/S button didn't have any response along with the "sport shift" function by pushing it left and right (didn't have any response) and the transmission didn't shift, it stayed in first. I had to turn off the car to get it unstuck.

I guess it'll have to go to the dealer. I'm wondering if that Light Sensor error message even has anything to do with the light sensor. It seems to be working fine. All these other things are going wrong instead.

benzmodz

Sounds more like a front fuse box is failing. You didnt by chance take some of that free advice on here that says "just disconnect the battery" any old time you want to reset things. It can cause stuff like this to happen.

bnz616

That doesn't sound good =(. Nope, never disconnected the battery before. The very first time I saw this "Light Sensor Visit Workshop" error message was when I was out of town for about 3 weeks and the first day I got back and started the car. Odd....do you really think it could be the problem? Mechanical wise, everything seems fine. Whats involved if it really is the front fuse box? And front fuse box meaning the one under the hood? Or maybe its a battery problem....would there be a low voltage message if the battery was weak?

I've been driving the car a lot today and that error message is coming up everytime i start up the car. And i think it really does seem like the car start up is a little weak. The lights dim a lot when i turn the car on and start it up.

Thanks.

bnz616

The battery is dead now. I opened the car door and noticed the dome lights didn't turn on and stuck in the car to start the car, but no response. I'm going to get the battery jumped and checked out, hopefully all those problems above were just from a dying battery.

benzmodz

Batteries do fall over and its not unusual since it is a service item that wears out. If the voltage of the battery was very low it doesnt explain erratic operation with the engine on.

Have the alternator checked too.

bnz616

Just had MB roadside come by and they changed the battery because it was a bad cell. Everything seems to be fine. I guess it has been about 3 years, although I don't know if the original owner changed the battery before.

If everything stays fine, then it was definately the battery. Like you explained, the low voltage was probably causing all the sensors and systems to act crazy.

Is checking the alternator a quick job or something I can do myself? If not, anywhere else you would recommend taking it to have it checked quickly besides the dealer.

jedandan

I am grateful for all the maintenance and troubleshooting-related posts on this forum, and would like to provide my contribution to this topic.

I drive a 2002 C230 Kompressor coupe, and the vehicle now has 190,000 km. I purchased the vehicle in 2005 with 49,000 km.

About 3 months ago (January) I recalled the first "Light Sensor Visit Workshop" error message. This message appeared when I would first start the car on a cold morning (e.g., less than -10 degrees Celsius). Over the next few weeks the message would appear more frequently, until it ultimately appeared every time the engine was turned-on. I did not think very much of the message at the time as all my lights were functioning properly; however, the error message was becoming more irritating.

About 8 weeks since the inception of the first message, upon starting the vehicle, the transmission got stuck in the first gear on two separate occasions. This occured within one week. The vehicle jerked into drive or reverse, and the W/S button didn't have any response when the vehicle was in the Parking gear. Likewise, when the vehicle was stuck in first gear, the "tiptronic" shifter did not respond. On both occasions I parked the car, turned off the engine, started-up again, and all mechanical functions operated without any noticeable problem.

To respond the re-occurring error message and the two noted transmission failures, I postulated that the car battery may be the root-cause, as the "starts" were hesitating more with time, and the lights were dimming during "start-up". I assumed that the light sensor (located on the windshield, behind the rear-view mirror mount) was the last electronic device in the vehicle circuitry. Consequently, the light sensor would be receiving the weakest signal (e.g., inadequate current) to perform its complete function.

Two weeks ago I changed the car battery. The change took no more than 20 minutes. The "Light Sensor Visit Workshop" message has not re-appeared since. The transmission functions without any issue.

Upon changing the battery, two functions had to be reset. The "ESP" needs to be reset by moving your steering wheel from knock-to-knock three times and the panoramic sunroof also needs to be reset. Consult your Driver's Manual for those details. It takes no more than a few minutes to complete both activities.

P.S. Two weeks before diagnosing the problem myself, I asked the Mercedes Dealership to perform a diagnosis and to rectify the issue. The technician "cleaned" the contact point with ground and tightened a bolt. This did not solve the problem and I was refunded the cost after I determined the actual root-cause. I presume an (inexperienced) apprentice technician tried to diagnose the problem; someone with experience should have noticed the hesitating start-up and dimming lights, and consequently, first checked the voltage.

Hope this information helps!

gt4awd

Your problem was due to low battery voltage. You need a new battery. I had that malfunction several times, replaced the battery, and never again...

c32kompressor

I get a left taillight bulb out, substitute light in use message but then it goes away and doesn't come back for a week or so? Is this bad wiring? Its a C32

jturkel

likely bad wiring. i have the same thing right now. and a left license plate bulb out as well. the warnings i get for those are random. i just ignore them. they are likely wiring related

southernwake

I am having a similar problem, I did a search and found this thread.

Last weekend I was just looking over my engine bay checking hoses etc. I forgot to place the pop off plastic piece that covers the pulleys back and I left it sitting on the top of the motor and closed the hood on it( it didnt break either) I finished what I was doing and left my key sitting in the slot under the radio over night. Next day I went to start the car to pull it out of the shop and it would just click. So I hooked up the battery charger and after charging it was fine except this message "Light Sensor Visit Workshop", which went away after I shut it off and started again . Drove it all week no issues.

Tonight I was headed back to my place after spending Friday evening and all day Saturday with some friends, I could not even unlock the car with the remote, opened the door with the mechanical key and no lights. So I had my buddy jump me off and car started and I got the "Light Sensor Visit Workshop" message. Turned car off and started again and it was gone. Went to leave and the transmission would not shift into any other gears automatically or manually, So I went back and sat at my friends house for 10 minutes while car ran and I watched over it. Hopped in and checked to see if I could manually get the gears to change on the LCD and they did and I drove home with zero issues.

My concern is why would my battery be dieing when the car sits for roughly 24 hours? I work 12-15 hours a night and last week it never struggled or acted like it had a weak battery after the first incident...so what gives? Nothing is getting left on, I thought maybe it was due to the IR key being left in the car overnight or maybe the hood open sensor didnt like the plastic piece in there incorrectly. Any advice?

Andrew

Gramma_Benz

Do a search for "Seat Module Battery drain" then just do this and you will be fine.

https://mbworld.org/forums/c-class-w203/262131-temjinx2s-20-seat-control-battery-drain-fix.html#post3068555

Remember if your battery is low, charge it up before driving or your alternator will prematurely fail. I speak from experience.

Good Luck!

loudandheard

Our cars require a specific amount of power to start and run. If your battery is over 3+ years old, then it may be time for a new battery. Gramma is right about the seat control modules draining your battery, but their are a few other areas that can drain your battery as well. The overhead console that controls the lights and the sunroof can cause this problem, the alarm, and if you have navigation, the fan may not turn off completely and run the battery down.

Change the battery first and then see if the issue persists, if it does then you can start the trouble shooting process to see what is draining your battery. Good luck.

southernwake

I thought there was a slight chance that maybe it was the battery, I have had the care for a month and last weekend was the first issue I have had with the battery.

I am going to have a friend of mine use his battery tester bat his shop to determine if it is good or not, but I may still end up replacing it.

How will the sunroof, over head light kill it? I would assume from staying on with the light but the sunroof I am curious about. I do not have navigation so that I can rule out.

Thanks for the advice,
Andrew

loudandheard

I believe that there is a module that controls the lights and the sunroof and it can begin to drain the battery.

We have a ground loop system that is always on, but it shuts off on it own. When some thing opens the loop, it will continue to run, draining your battery.

southernwake

Okay. well that makes sense. I was aware of the ground loop but I can see if it or a certain section of it fails to turn off then it drains the battery. Pretty simple. Thank you for clearing that up for me.

I have disconnected the passenger side seat module, since what I have discovered in my research on this topic is that this side seems to be the side that acts up the most. I will see how it does over the next few days. Obviously if my battery is shot when I get it tested tomorrow I will replace it and still try to find this parasitic drain!

If anyone has any other ideas I am open to any of them, this has become quite a "fun" experience.

Thanks,
Andrew

loudandheard

If it is your seat control modules, definitely take a look at the thread that gramma recommended https://mbworld.org/forums/c-class-w...ml#post3068555

southernwake

I have actually book marked that thread on my laptop so that I wont have to search for it again. I have unplugged it for now just to see if it happens again. If it does not happen again I will know that I have narrowed it down to the seat module and then do the fix.

Being a engineering major and working in warehouse automation I am interested to see if I can take the module itself out and open it up and see what could be causing the issue, I thought I ran across someone who posted a diagram for the module while I was researching the battery drain issue.

pablom617

I change my battery this morning, my car was doing the same thing. It was definitely the battery.

C_DirtyTwo

Car sat for 4 days while I was on a trip, came back home and it started up fine, drove it all day no issues. Next day, I go to start it up and it barely starts, new error in the display "Light Sensor Visit Workshop". turn off the car and restart it with no issues or malfunctions.

Today the car won't start. Battery seems to be dead.

I thought it was the seat control module, but there's no way it would have lasted all weekend (4 days) without draining it. Any suggestions? Just need a new battery perhaps?

pablom617

Definetely sounds like the battery. My car started doing all kinds of crazy stuff when the battery was going bad. My windows wouldn't work and I couldn't open the locks.