Mercedes-Benz Marco Polo 2017 Owner's Manual Supplement page 52

Auxiliary heating (auxiliary warm-air heater)
50
Problem
The auxiliary heating
switches off.
The auxiliary heating
switches off.
The auxiliary heating
switches off.
The auxiliary heating
switches off.
Possible causes/consequences and M Solutions
The interior temperature sensor is faulty. The temperature in the living
area cannot be set.
After switching the auxiliary heating on again, it continuously heats the
living area.
X
Switch the auxiliary heating on again without changing the settings
for the living area.
X
Have the interior temperature sensor checked at a qualified spe-
cialist workshop.
Undervoltage. The voltage was lower than 10.5 V for more than 20
seconds.
X
Charge the auxiliary battery (
G
Risk of accident
The auxiliary heating is overheated. The motor or heating unit is faulty.
If you switch the auxiliary heating on ten times in a row while this fault
is still detected, auxiliary heating operation is disabled.
X
Do not switch on the auxiliary heating.
X
Have the auxiliary heating checked at a qualified specialist work-
shop.
G
Risk of accident
Failed starting attempt. There is a lack of fuel, or the motor or heating
unit is faulty.
If you switch the auxiliary heating on ten times in a row while this fault
is still detected, auxiliary heating operation is disabled.
X
If the fuel tank is less than one quarter full - refuel at the next filling
station.
Then, start the auxiliary heating several times until the fuel lines are
full.
X
Have the auxiliary heating checked at a qualified specialist work-
shop.
The auxiliary heating diagnostic interface is faulty. Warning messages
are no longer displayed. Normal operation is possible.
The auxiliary heating control unit monitors all functions.
X
Have the auxiliary heating checked at a qualified specialist work-
shop.
Operation of the auxiliary heating is blocked.
X
Have the auxiliary heating enabled and checked at a qualified spe-
cialist workshop.
Y
page 63).