got a tail light message on instrument panel.
when checking all taillights are in working order.
Also the fuel consumption message is weird - when coming to a stoplight or leaving a stoplight the indicator shows a consumption of 99l/100km. after a few hundred yards it goes down to under 40, then shows the reasonable amount of 8l/100km. It never did that before

 

Don't forget to also check the third brake light on the rear deck.

 

that one works also

 

Both elements? Sometimes one of the two elements can burn out and signal the light but it still looks ok.

 

Firstly, what year is your LS 430.

if its 2001~2003, try the following:
1- start the car without pressing any pedals and have all lights off. If no alerts show continue to step 2.
2-Briefly press on the brake pedal. If you get an alert, then your lower brake-area lights OR your middle third brake light is out. They use dual-filament 7443. If you dont get a bulb out alert, go to next step.
3-Twist the light **** to headlight-on. If you now get an alert even without pressing on the brake, then your upper brake-area light are out. They use single filament 194 bulbs.

I dont have much info on facelift 2004~2006 models, they use soldered-in LED's. If those are out it might give an alert on the dash. The easiest way to fix is to change the entire light assembly. The cheapest way would be to take the assembly out and apart, and desolder the broken LED's and then solder in new LED's.

Edit: oh and are you sure its alerting for rear bulbs? It should tell you which part of the car bulbs are out, front or rear. The front marker-indicators and i THINK the high-beams (when used as DRL) also throw an error if they are burnt out.

 

thank you for the excellent diagnosis.
Out of curiosity i removed the cover flap to see how to get at the bulbs. I saw one light socket completely loose from the socket holder. Put the socket back on and the alert cleared
thanks again