Mercedes-Benz 2013 M Class - Manual (Page 328)

Problem Possible causes/consequences and M Solutions
?
The red coolant
warning lamp lights up
while the engine is
running and the coolant
temperature gauge is
at the start of the scale. The temperature sensor for the coolant temperature gauge is
defective.
The coolant temperature is no longer being monitored. There is a
risk of engine damage if the coolant temperature is too high.
X Pull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions. Do not continue
driving under any circumstances.
X Secure the vehicle against rolling away ( Y page 179).
X Consult a qualified specialist workshop.
326
Warning and indicator lamps in the instrument cluster
On-board computer and displays