Handling
Work through the faults with
the relevant test plans
Steady state is reached only
after lengthy engine running.
Check settings (adapt specified
temperature to ambient
temperature as necessary),
check settings (adapt specified
temperature to ambient
temperature as necessary) to
have more stop phases. If the
adjustment is OK, explain to
the customer that the A/C
requires a certain time to
respond to the temperature
Advise the customer that the
defrost function is causing the
restart
Restart due to ambient
temperature change so that
climate control can be ensured.
Explain to the customer that a
restart is performed if the
selected interior temperature is
not reached.
Advise the customer that this
will improve safety
Advise the customer that this
will improve safety
Advise the customer that the
restart is executed due to a
Low/High AC setting.
Advise the customer that this
will improve safety
Advise the customer that due
to high levels of humidity in
the evaporator it was necessary
to restart in order to avoid
window misting (mostly at
very high ambient
temperatures/high humidity
levels)
Advise the customer that the
"Manual air recirculation"

recirculation" elapsed *)

PSD (permissible stop
duration) "Air distribution top" Customer setting air vent up
elapsed *)

Evaporator temperature
difference from setting

No data

Stop release for A/C comfort
adaption

Adaption channel to influence
the permitted influence of
start/stop on the interior
comfort was changed.
Important note: This adaption
channel can also be used to set
a general stop prohibition and
an immediate restart by the air
conditioner

Interior comfort humidity too
high

Interior humidity increased
sharply

Interior vent difference to
setting

Temperature of climatecontrolled air from vents
(chest vents and/or footwell
vents) differs too much from
AC control settings

Interior temperature difference
to setting

Interior temperature varies too
widely from preset specified
temperature.

Maximum cooling and heating
set

At least one temperature
preselector was set to "HI" or
"LO".

Head area heater

Customer has activated neck
heating (convertible only)

maximum stop duration
reached

Maximum stop duration has
elapsed

setting will reduce the stop
duration in order to avoid
window misting.
Advise the customer that the
"Air distribution top" setting
can only enhance interior
comfort to a limited extent, so
the stop duration will be
reduced.
Necessary evaporator
temperature for comfortable
interior climate control was
exceeded. Restart to set the
optimal evaporator
temperature was required.

Advise the customer that his
desire to shorten the stop
duration was the reason for the
restart

Advise the customer that the
restart was carried out to
restore optimal interior
comfort.
Advise the customer that the
temperature of the climatecontrolled air is not yet
sufficient for optimal interior
climate control, so the stop is
prevented
Advise the customer that the
restart was carried out to
restore optimal interior
comfort.
Advise the customer that the
restart is executed due to a
Low/High AC setting.
Advise the customer that an
immediate restart is executed
due to the high current
consumption of the neck
heating.
Advise the customer that the
maximum stop duration had
been reached and a restart was
necessary because setting of

the optimal interior comfort
could no longer be ensured.

Stop prohibitions
Reason

Cause:

Epsilon (output) blow-out too
low or too high

Air conditioner not yet
stabilised - no steady state
reached.

Defrost active

Customer has pressed the
Defrost button

Ambient temperature too low
or too high

Ambient temperature outside
nominal range

Epsilon (output) interior
temperature too low or too
high

Customer temperature request
too low/high

Gradient dew point interior too The rise in air humidity is too
high
high
Risk of misting

Risk of windscreen misting

At least one specified
temperature is High or Low

Customer AC setting High or
Low

Comfort humidity

Interior humidity ideally 50...
60%

PSD (permissible stop
duration) "Epsilon_Fog"
elapsed *)

Risk of windscreen misting

PSD (permissible stop
duration) "Manual air
recirculation" elapsed

Customer setting manual air
recirculation

PSD (permissible stop
duration) "Air distribution top" Customer setting air vent up
elapsed

Handling
Steady state is reached only
after lengthy engine running.
Check settings (adjust
specified temperature to
outside temperature if
necessary) in order to have
more stop phases If the
adjustment is OK, explain to
the customer that the A/C
requires a certain time to
respond to the temperature.
Advise the customer that the
defrost function is preventing
the stop
Ambient temperature too
high/low. A stop would be
uselessly short due to the very
high heating/cooling demand.
Explain to the customer that a
stop is prevented if the
selected interior temperature is
not reached.
Advise the customer that this
will improve safety
Advise the customer that in the
event of a risk of windscreen
misting the stop is prevented
Advise the customer that the
stop is prevented due to the
Low/High AC setting
Advise the customer that this
will improve safety
(windscreen misting)
Advise the customer that this
will improve safety
(windscreen misting)
Advise the customer that the
stop is prevented due to the
"Manual air recirculation"
setting
Advise the customer that the
"Air distribution top" setting
can only maintain interior

comfort to a limited extent, so
a stop prohibition is enforce.
PSD (permissible stop
duration) emergency running
elapsed / PSD with active
DTC

A fault is entered in the
climate control CU

Evaporator temperature
difference from setting

No data

Interior vent difference to
setting

Temperature of climatecontrolled air from vents
(chest vents and/or footwell
vents) differs too much from
AC control settings

Stop release for A/C comfort
adaption

Adaption channel to influence
the permitted influence of
start/stop on the interior
comfort was changed.
Important note: This adaption
channel can also be used to set
a general stop prohibition and
an immediate restart by the air
conditioner

Interior comfort humidity too
high

.

Interior temperature difference
to setting

Interior temperature varies too
widely from preset specified
temperature.

Maximum cooling and heating
set

At least one temperature
preselector was set to "HI" or
"LO".

Head area heater

Customer has activated neck
heating (convertible only)

Basic setting active

Diagnostic routine is active

Read fault memory
Necessary evaporator
temperature for comfortable
interior climate control was
exceeded. Restart request to
avoid interior heat-up/window
misting
Advise the customer that the
temperature of the climatecontrolled air is not yet
sufficient for optimal interior
climate control, so the stop is
prevented

Advise the customer that the
above adaption channel is set
so that a stop is always
prohibited

Advise the customer that the
stop was prevented due to high
humidity (risk of window
misting)
Explain to the customer that a
stop is prevented if the
selected interior temperature is
not reached.
Advise the customer that the
stop is prevented due to
Low/High AC setting
Advise the customer that a
stop is prevented due to the
high current consumption of
the neck heating.
Not relevant to customer

09 - Electronic central electrics
Start requests
Reason
Parking aid active

Parking assistant active

Trailer manoeuvring system
active

Cause:
The parking aid button was
pressed or reverse gear was
engaged. During this time the
start-stop function is
deactivated.
The parking assistant button
was pressed or reverse gear
was engaged. During this time
the start-stop function is
deactivated.
If the trailer manoeuvring
system is active (activation
button indicates the active
function), the start-stop
function is deactivate and a
start request is sent

Defrost active

Customer has pressed the
Defrost button.

Ambient temperature

Ambient temperature outside
nominal range

Maximum cooling and heating
set

At least one temperature
preselector was set to "HI" or
"LO".

Interior temperature difference
to setting

Interior temperature varies too
widely from preset specified
temperature.

Interior vent difference to
setting

Temperature of climatecontrolled air from vents
(chest vents and/or footwell
vents) differs too much from
AC control settings

Risk of misting

Risk of windscreen misting

Interior comfort humidity too
high

Interior humidity increased
sharply

Stop release for A/C comfort
adaption

Adaption channel to influence
the permitted influence of
start/stop on the interior
comfort was changed.

Handling
Advise the customer that this
action deactivates the startstop function.
Advise the customer that this
action deactivates the startstop function.
Advise the customer that an
active trailer manoeuvring
system deactivates the startstop function.
Advise the customer that the
defrost function is causing the
restart
Restart due to ambient
temperature change so that
climate control can be ensured.
Advise the customer that the
restart is executed due to a
Low/High AC setting.
Advise the customer that the
restart was carried out to
restore optimal interior
comfort.
Advise the customer that the
temperature of the climatecontrolled air is not yet
sufficient for optimal interior
climate control, so the stop is
prevented
Advise the customer that this
will improve safety
Advise the customer that the
restart was carried out to
restore optimal interior
comfort.
Advise the customer that his
desire to shorten the stop
duration was the reason for the
restart

Important note: This adaption
channel can also be used to set
a general stop prohibition and
an immediate restart by the air
conditioner
Stop prohibitions
Reason
Parking aid active

Parking assistant active

Cause:
The parking aid button was
pressed or reverse gear was
engaged. During this time the
start-stop function is
deactivated.
The parking assistant button
was pressed or reverse gear
was engaged. During this time
the start-stop function is
deactivated.

Defrost active

Customer has pressed the
Defrost button

Ambient temperature

Ambient temperature outside
nominal range

Maximum cooling and heating
set

At least one temperature
preselector was set to "HI" or
"LO".

Interior temperature difference
to setting

Interior temperature varies too
widely from preset specified
temperature.

Interior vent difference to
setting

Temperature of climatecontrolled air from vents
(chest vents and/or footwell
vents) differs too much from
AC control settings

Risk of misting

Risk of windscreen misting

Interior comfort humidity too
high

.

Stop release for A/C comfort
adaption

Adaption channel to influence
the permitted influence of
start/stop on the interior
comfort was changed.

Handling
Advise the customer that this
action deactivates the startstop function.
Advise the customer that this
action deactivates the startstop function.
Advise the customer that the
defrost function is preventing
the stop
Ambient temperature too
high/low. A stop would be
uselessly short due to the very
high heating/cooling demand.
Advise the customer that the
restart is executed due to a
Low/High AC setting.
Explain to the customer that a
stop is prevented if the
selected interior temperature is
not reached.
Advise the customer that the
temperature of the climatecontrolled air is not yet
sufficient for optimal interior
climate control, so the stop is
prevented