RPM climbs but speed does not — the discs are not holding torque. The electronics catch this from the mismatch between engine speed and the gearbox output shaft, and log a code before the difference is noticeable from the cab. Do not keep pulling a loaded truck uphill like this.
The gearbox or clutch has gone into limp mode: some gears may be unavailable and an automated box may stop shifting under load.
The main risk is being left on a climb with no gear and rolling back. Do not take a loaded truck into the hills; reaching level ground and a shop is fine.
That said, the manufacturer flags this code as critical — if in doubt, it is safer to stop and check on the spot.
The answer depends on the code, not the light. A yellow light is a warning; a red one means do not move. But even under a yellow light there are faults that require stopping right away — low oil pressure, overheating, lost brake pressure. Enter the code — the reference will tell you plainly whether to keep driving or stop.
Know the code number? Type it into the search — or paste the whole list from the scanner and we will show which fault is the real one.