A yellow light with triangle turns on while driving audi a4

https://www.justanswer.com/audi/1qbl7-warning-light-showing-yellow-circle-triangle.html

Yellow circle, with triangle and exclamation mark – The Electronic Stability Program (ESP) dashboard light flashes if the ESP or traction control is activated whilst driving. If ESP or traction control has been switched off, it will light up continuously. If ESP or traction control is not turned off and the warning light illuminates continuously, it indicates a problem and malfunction with either ESP or traction control.

Will need to have it daignosed by a professional and perform repair that is needed.
The "check engine" light is on because of a problem that the computer has sensed within the sensors of a faulty circuit.

The triangle is on because the problem is also effecting other modules within the vehicle.

Perform diagnostics to determine problem and repair problem..

AIRBAG LIGHT WILL STILL STAY ON.TEST DRIVE WILL TURN UR ESP LIGHT OFF. THE TRIANGLE LIGHT AS U MENYIONED.LET ME KNOW .........

Engine management light, some problem in engine, might be simple cure, disconnect car battery for ten mins , might reset it, if not dealer or guy with diagnostics can reset

it means that you have a fault in your brake system
take your audi to an audidealership and have them check the abs codes (antilock braking system)
http://net.jasonpearce.com/chronicle/audiwarnings.html

Did you found out the problem? i have the same problem and i want to find out,

Katielouiser I have the same icon come on each time i start my 1996 Audi A4 and if I don't wait till it goes off before starting the car it will immobilise the engine soon after starting. But if I wait till it goes off before proceeding with starting, the engine will continue to run till I stop and turn the ignition off- only to repeat this all over again when I have to drive somewhere again. It can be a pain when ones in a hurry, and embrassing to say the least when you have passengers.

get a scan done on the central convenience that will give you a code to start with,but it sounds like a controller fault

Usually it Means that you are low on Oil or Coolant.