I am consistently getting the “lamp defective” error message on my 210 E320. All the lights are working but the error message still erratically keeps appearing. My mechanic does not have the appropriate OBD and t Ellis me that I need to take my car to a specialist Mercedes dealer. Any help to rid this annoying error message would be very much appreciated. Thank you in advance.


Have you replaced any light bulbs recently? If all the lights work the error is because a bulb with the wrong wattage has been used.

LED bulbs will also give this error.

I would check all the bulbs first. Especially the parking bulbs by the front bumper and the license plate (rear).

Hi, many thanks for the reply. I replaced the right rear stop and tail light bulb i.e. 12 volt 4 watt, I also tried a 12 volt 5 watt. Both worked but the error message kept appearing. I replaced the 12 volt 4 watt bulb again. At this stage all lights are working but the error message keeps popping up. I spoke to my local mechanic and he said he no longer has the E320 OBD (round type) and that Mercedes will not sell him parts even if he was able to find an error. Do you know if the proper OBD has the capacity to delete the error message? Cheers, Eric

You won't be able to delete the problem, but the correct scanner can tell you which bulb is the problem. 

My guess is that a bulb with the wrong wattage has been installed. 

Have you replaced any other bulbs in the last few months? 

Thanks for the reply. See my earlier post. I replaced the right rear stop  and tail lightbulb. Replaced with a 12 volt 21x4 watt bulb as per handbook, tried a 21x5 watt, but the error still appears. Put the 21x4 watt back in but no change. I also tried taking the same bulb from left rear stop and tail light, again the error showed up. The error is very erratic i.e sometimes on straight away other times I can travel for kilometres showing no errors and then, without any reason (like applying the brakes) it reappears. I notice that heat (hot days seem to bring on the error message very quickly) whereas on cold days it takes a lot longer! Frustrating to say the least! Again thanks for replying I appreciate your input. Cheers, Eric

I used to have a W211 and it had a common problem with the socket on the rear tail light. Check it. Either replace it or clean it a bit with sandaper and use some dielectric grease.

Let us know if the warning message comes back.


Many thanks for your reply. I did exactly what you recommended and actually replaced the right rear lense. It worked for a little while but sadly it has again reverted to the error message returning. I have checked all of the bulbs and they are all of the correct wattage and they are all working! I have booked the car into Poyser Mercedes Benz Bendigo next Tuesday. I spoke to their head mechanic and he tells me that their computer should bring up the cause of the error message. So, hopefully they will be able to stop the error message. I really appreciate your reply so many thanks and all the very best. Cheers, Eric

Hi Eric, 


Thanks for the update. Yes Star Diagnostic Scanner will tell you what circuit is triggering the warning.

Let us know what they find out.

Star Diagnostics or any professional level scanner will show which circuit is throwing the error. 

Hi Everyone,

The computer check did NOT detect an error. This is in spite of the “lamp defective” error being displayed on the dashboard! The dealer says they will have to complete a full diagnostic check which means they will have to remove every lamp on the car and check them individually. Time consuming and expensive because they couldn’t give me price and it could take hours at about $140 an hour! I am considering my options, including trying another dealer, before I make a final decision.  In the meantime I will check and recheck all of the exterior lights. Very frustrating to say the least and I am very annoyed that the Mercedes computer did not find the error. I will keep everyone on this site advised of the outcome. Thanks to everyone for your replies, they are very much appreciated. Cheers, Eric

Eric did the error display on the instrument cluster but not on the scanner? 

If yes there is a a good chance you have a defective instrument cluster. 

If no, then you may have to perform the diagnostics when the error is on the instrument cluster. 

BTW where are you located? 



The error message was on the instrument cluster but not detected by the scanner (I wasn't allowed to view the test - private workshop). I live just North of Melbourne Victoria Australia. Thanks for you input. Cheers, Eric

I have finally fixed the “lamp defective” error message. Took the car to DRC AUTO ELECTRICAL based in Kyneton Victoria. They ran a diagnostic check and found quote “the fuse box assembly was faulty causing intermittent connection to the right rear stop/tail light”. To save the expense of replacing the entire fuse box they bypassed the faulty connection with an accessory fuse holder fitted in behind the fuse box. Works well and no more error messages. Hopefully this fix will work permanently. TYVM to everyone who replied to my posts.


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