Amber/Red
The colour helps indicate urgency, but exact behaviour can vary by manufacturer.
Dashboard Warning Light
AdBlue / DEF
Diesel exhaust fluid low/fault. The usual first step is: Top up/service.
Inspect soon
Use this as a quick triage label before confirming in your owner manual.
Top up/service
Check the matching manual page for your exact brand, model and year when possible.
What it usually means
Diesel exhaust fluid low/fault.
What to do next
Top up/service. If the vehicle feels unsafe, stop in a safe place and arrange professional inspection.