White/Amber/Red
The colour helps indicate urgency, but exact behaviour can vary by manufacturer.
Dashboard Warning Light
AdBlue / DEF
Fluid low, refill required, or SCR/DEF fault; red may prevent restart. The usual first step is: Top up the correct fluid promptly; service if fault/red.
Varies by state
Use this as a quick triage label before confirming in your owner manual.
Top up the correct fluid promptly; service if fault/red
Check the matching manual page for your exact brand, model and year when possible.
What it usually means
Fluid low, refill required, or SCR/DEF fault; red may prevent restart.
What to do next
Top up the correct fluid promptly; service if fault/red. If the vehicle feels unsafe, stop in a safe place and arrange professional inspection.
Can I drive with the AdBlue / DEF light on?
Treat the AdBlue / DEF light as urgent if it is red, flashing, or the car feels unsafe. Stop in a safe place and check the owner manual before continuing.
First step: Top up the correct fluid promptly; service if fault/red. If the warning appears with noise, smoke, overheating, poor braking, heavy steering, or reduced power, stop safely and get professional help.
Quick answers
What does the AdBlue / DEF dashboard light mean?
Fluid low, refill required, or SCR/DEF fault; red may prevent restart.
Can I drive with the AdBlue / DEF light on?
Treat the AdBlue / DEF light as urgent if it is red, flashing, or the car feels unsafe. Stop in a safe place and check the owner manual before continuing.
What should I check first when the AdBlue / DEF light appears?
Start with this step: Top up the correct fluid promptly; service if fault/red. Then confirm the exact symbol behaviour in the owner manual for your car brand, model and year.