Mercedes-Benz 2015 M-Class Operator's Manual page 169

Problems with the engine
Problem
The engine does not
start. The starter motor
can be heard.
The engine does not
start. You cannot hear
the starter motor.
Vehicles with a gaso-
line engine:
The engine is not run-
ning smoothly and is
misfiring.
The coolant tempera-
ture gauge shows a
value above 248 ‡
(120 †).
Possible causes/consequences and M M Solutions
There is a malfunction in the engine electronics.
R
There is a malfunction in the fuel supply.
R
Before attempting to start the engine again, turn the SmartKey
X
in the ignition back to position 0 or press the Start/Stop button
repeatedly until all indicator lamps in the instrument cluster go
out.
Try to start the engine again (
X
long and frequent attempts to start the engine as these will drain
the battery.
If the engine does not start after several attempts:
Consult a qualified specialist workshop.
X
The on-board voltage is too low because the battery is too weak or
discharged.
Jump-start the vehicle (
X
If the engine does not start despite attempts to jump-start it:
Consult a qualified specialist workshop.
X
The starter motor was exposed to a thermal load that was too high.
Allow the starter motor to cool down for approximately two
X
minutes.
Try to start the engine again.
X
If the engine still does not start:
Consult a qualified specialist workshop.
X
There is a malfunction in the engine electronics or in a mechanical
component of the engine management system.
Only depress the accelerator pedal slightly.
X
Otherwise, non-combusted fuel may get into the catalytic con-
verter and damage it.
Have the cause rectified immediately at a qualified specialist
X
workshop.
The coolant level is too low. The coolant is too hot and the engine
is no longer being cooled sufficiently.
Stop as soon as possible and allow the engine and the coolant to
X
cool down.
Check the coolant level (
X
notes as you do so and add coolant if necessary.
page 159). Avoid excessively
Y
page 391).
Y
page 369). Observe the warning
Y
Driving
167
Z