Which bulb??!!

Hi Ian

Sounds like a fault in the system that detects these issues?

A sender unit maybe or a circuit malfunction?

Think this will be a garage job so they can hook up a diagnostic system to check it out.

Bugs

It could be that one of the bulbs has developed a high resistance. If you examine each bulb you may find one that looks black inside and this may be the culprit. Sometimes bulbs need to be changed in pairs as the one on the other side, being older, has a higher resistance than the new bulb. The computer senses the difference in resistance and thinks one bulb has failed.

Think you are right, Bugs. But it will have to wait for the next service.

Pee......same answer really. Check every bulb? No, leave it to the experts with the plug in computer, I think.

The bulb check isn't going to monitor every single bulb/lamp on your car. It's likely to check the side lights front & back and headlights if they are normal filament lamps. As suggested above, it could just be a tired bulb or high resistance contact. Another suggestion is, are all the rear bulbs working as they should? eg some cars with CANbus will use an alternative bulb if one has blown, so though you have two/four working tail lights, the car will show up a fault as the incorrect bulbs are on. Not all faults need the relevent 'computer' ... just a little common dog 

Just in case it catches you out, be aware that some manufactures fit a single filament bulb to operate as 2 different lights by just changing the light intensity. Vauxhall did this on some models for the Stop & Tail lights. I've know it in the past for people to think the wrong bulb had been fitted.

Bulbs are cheap (cheaper than a Garage hourly rate) so it's worth taking the advice above and looking at, and changing any that look discoloured or damaged / corroded in any way.  

But all bulbs are working normally......

HAHA !

Just  wait  til  you  are  driving  along  in  front  of  young  Constable Keenandclean !  He  will  tell  you  exactly  which  bulbS  are  defective  and  for  only  a  few  quid  each  !! 

It would be a novelty to see Constable Keenandclean out on the street around here, Brian.......

Fully agree with your above opinions Peegeenine. This can also happen on older vehicles as CAN-bus circuitry on vehicles has now been around since the early 2000's. The CAN-bus circuitry on older vehicles can deteriorate with age and cause changes in circuitry resistance and control signal problems just to mention a few. There are only a few ways of possibly curing said CAN-bus wiring age related problems. Very few dealers are able to find & cure such problems as most staff have no idea where to look as a Plug-in-job does not tell them. In many modern cars; bulb failure systems now detect LED lights as well, in your case, prime suspect to me (if not bulbs) is your highline-stoplight. Why do I say that? I've known on many occasions the high-line stoplight be found to have condensation trapped inside the LED unit. Possible cure! Try drying it out with a hairdryer both inside & out the best you can, then check to see if your bulb failure light goes out.

The car is only 4.5 years old........30k miles......