Disappearing Fault code

[Coddie]

Morning All. Has anyone got any thoughts on a problem I'm having.
The car I'm talking about is a 2008, CLC 350 with the M272 engine.The other day I had a message on the dashboard saying that the 3rd brake light had failed on checking it was working fine. The rest of the day and the following one it was fine.
Yesterday when my wife was driving it, the message reappeared along with the engine management light. The EM warning stayed on until she returned home, when I plugged the code reader in the I got the no fault codes message and on restarting the engine the warning had gone. The only thing I can see is there is some condensation on the inside of the 3rd brake light lens..
I've done a quick check of the loom as it enters the tailgate all looks fine.
Any thoughts or pointers please
Thanks

 

[Petrol Pete]

Could this be another 'low battery' thing ? I have not experienced it myself but there have been many threads that mention all sorts of spurious 'alarms' when the cars main battery is weak .

 

[Coddie]

Could this be another 'low battery' thing ? I have not experienced it myself but there have been many threads that mention all sorts of spurious 'alarms' when the cars main battery is weak .

Thanks for the reply..I doubt it's the battery, it's quite new and the first instance of the message was after about 400 miles of driving..I will check the alternator output just in case..it's driving spot on though.
Appreciate your help

 

[ToeKnee]

Don't some Mercedes lamp units have spare bulbs so that when the main bulb blow the spare takes over so you don't drive without a working lamp, if so then the blown bulb might need replacing?

 

[Coddie]

Don't some Mercedes lamp units have spare bulbs so that when the main bulb blow the spare takes over so you don't drive without a working lamp, if so then the blown bulb might need replacing?

I've had a good look at all the bulbs/LEDs and they're all working. In addition took the car to a friendly local garage, who put their analyser on it.. no codes on the system. I've given the car a good run around, no fault light. Odd one!

 

[zipdip]

Have you got any damp in the boot.

 

[ATR]

Could this be another 'low battery' thing ? I have not experienced it myself but there have been many threads that mention all sorts of spurious 'alarms' when the cars main battery is weak .

Is it an approved battery? Sometimes can have the same effect as a low battery.

 

[Coddie]

Have you got any damp in the boot.

Actually yes, there's signs of a small amount of condensation in the 3rd brake light unit lens

 

[Coddie]

Is it an approved battery? Sometimes can have the same effect as a low battery.

It's a Varta, according to the specialist battery retailers I use it is suitable for the vehicle

 

[BlackC55]

Some code readers will not pick up all codes.