2014 MERCEDES-BENZ C-CLASS SALOON engine

Key
Display messages
Possible causes/consequences and
M
MSolutions Â
Key does not Key does not
belong to vehicle belong to vehicle You have put the wrong key in the ignition lock.
X Use the correct key. Â
Replace key Replace key The key needs to be replaced.
X Visit a qualified specialist workshop. Â
Change key batter‐ Change key batter‐
ies ies The key batteries are discharged.
X Replace the batteries (Y page 94).Â
Key not detected Key not detected
(white display mes-
sage) The key is currently undetected.
X Change the location of the key in the vehicle.
If the key still cannot be detected: X Insert the key into the ignition lock and turn it to the desired
position. Â
Key not detected Key not detected
(red display message) The key is not in the vehicle.
A warning tone also sounds.
If the engine is switched off, you can no longer lock the vehicle
centrally or start the engine.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle to prevent it from rolling away (Y page 207).
X Locate the key.
X Press aon the steering wheel to confirm the display mes-
sage. 350
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions Because there is interference from a strong source of radio waves,
the key is not detected whilst the engine is running.
A warning tone also sounds.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle to prevent it from rolling away (Y page 207).
X Operate the vehicle with the key in the ignition lock if necessary. Â
Remove starting Remove starting
button, then button, then
insert key insert key The key is continually undetected.
The key detection function has a temporary malfunction or is
faulty. A warning tone also sounds.
X Insert the key into the ignition lock and turn it to the desired
position.
X Visit a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
Safety
Seat belts Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions ü
N
Only for certain countries: the red seat belt warning lamp lights up for
6 seconds after the engine starts.
The seat belt warning lamp reminds the driver and front passenger to fasten
their seat belts.
X Fasten your seat belt (Y page 49).ü
N
Only for certain countries: the red seat belt warning lamp lights up after the
engine starts. In addition, a warning tone sounds for up to 6 seconds.
The driver's seat belt is not fastened.
X Fasten your seat belt (Y page 49).
The warning tone ceases. Wa
rning and indi cator lamps in the instrument cluster
351On-board computer and displays Z

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions ü
N
The red seat belt warning lamp lights up after the engine starts, as soon as
the driver's or the front-passenger door is closed.
The driver or passenger has not fastened their seat belt.
X Fasten your seat belt (Y page 49).
The warning lamp goes out.
There are objects on the front-passenger seat.
X Remove the objects from the front-passenger seat and stow them in a
secure place.
The warning lamp goes out. ü
N
The red seat belt warning lamp flashes and an intermittent audible warning
sounds.
The driver or passenger has not fastened their seat belt. At the same time, you are driving faster than 25 km/h or have briefly driven faster than 25 km/h.
X Fasten your seat belt (Y page 49).
The warning lamp goes out and the intermittent warning tone ceases.
There are objects on the front-passenger seat. At the same time, you are
driving faster than 25 km/h or have briefly driven faster than 25 km/h.
X Remove the objects from the front-passenger seat and stow them in a
secure place.
The warning lamp goes out and the intermittent warning tone ceases. 352
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Safety systems
Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions J
N
The yellow brake system warning lamp lights up while the engine is running
or the ECO start/stop function is activated.
Hybrid vehicle: the yellow brake system warning lamp is shown in driving
condition READY.
G WARNING
The brake system is malfunctioning and the braking characteristics may be
affected.
There is a risk of an accident. X If the multifunction display shows a display message, please observe this.
X Drive on carefully.
X Visit a qualified specialist workshop. J
N
The red brake system warning lamp is lit while the engine is running.
Hybrid vehicles: the red brake system warning lamp is shown in driving con-
dition READY.
A warning tone also sounds.
G WARNING
The brake boosting effect is malfunctioning and the braking characteristics
may be affected.
There is a risk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying attention to
road and traffic conditions. Do not continue driving under any circumstan-
ces.
X Secure the vehicle to prevent it from rolling away (Y page 207).
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction display. Warning and indicator lamps in the instrument cluster
353On-board computer and displays Z

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions J
N
The red brake system warning lamp is lit while the engine is running.
Hybrid vehicles: the red brake system warning lamp is shown in driving con-
dition READY.
A warning tone also sounds.
There is insufficient brake fluid in the brake fluid reservoir.
G WARNING
Braking efficiency may be impaired.
There is a risk of an accident. X Pull over and stop the vehicle safely as soon as possible, paying attention to
road and traffic conditions. Do not continue driving under any circumstan-
ces.
X Secure the vehicle to prevent it from rolling away (Y page 207).
X Do not top up the brake fluid. Topping up will not rectify the fault.
X Consult a qualified specialist workshop.
X Observe the additional display messages in the multifunction display. 354
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions !
N
The yellow ABS warning lamp is lit while the engine is running.
Hybrid vehicles: the yellow ABS warning lamp is shown in driving condition
READY.
ABS (Anti-lock Braking System) has been deactivated due to a fault. Therefore BAS (Brake Assist System), BAS PLUS, COLLISION PREVENTION ASSIST
PLUS, ESP ®
(Electronic Stability Program), PRE‑SAFE ®
, PRE‑ SAFE®
PLUS,
PRE‑ SAFE ®
Brake, HOLD function, hill start assist, ESP ®
trailer stabilisation,
Crosswind Assist, adaptive brake lights, STEER CONTROL, Active Lane Keep-
ing Assist and Active Blind Spot Assist are also deactivated.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions
listed above. The wheels could therefore lock if you brake hard, for example.
The steerability and braking characteristics may be severely affected. The
braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Observe the additional display messages in the multifunction display.
X Drive on carefully.
X Visit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other systems,
such as the navigation system or the automatic transmission, will be unavail- able. Warning and indicator lamps in the instrument cluster
355On-board computer and displays Z

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions !
N
The yellow ABS warning lamp is lit while the engine is running. A warning
tone also sounds.
Hybrid vehicles: the yellow ABS warning lamp is shown in driving condition
READY.
EBD is unavailable due to a malfunction. Therefore ABS, BAS, BAS PLUS,
COLLISION PREVENTION ASSIST PLUS, ESP ®
, ESP ®
trailer stabilisation,
Crosswind Assist, PRE‑SAFE ®
, PRE‑SAFE ®
PLUS, PRE‑SAFE ®
Brake, HOLD
function, hill start assist, adaptive brake lights, STEER CONTROL, Active Lane
Keeping Assist and Active Blind Spot Assist are also unavailable.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions
listed above. The front and rear wheels could therefore lock, for example, if you
brake hard.
The steerability and braking characteristics may be severely affected. The
braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Observe the additional display messages in the multifunction display.
X Drive on carefully.
X Visit a qualified specialist workshop. 356
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Warning/
indicator
lamp
N N
Signal type
Possible causes/consequences and M
MSolutions J÷
å!
N
The red brake warning lamp, the yellow ESP ®
and ESP ®
OFF warning lamp
and the yellow ABS warning lamp are lit while the engine is running.
Hybrid vehicle: The red brake warning lamp, the yellow ESP ®
and ESP ®
OFF
warning lamp and the yellow ABS warning lamp are shown in driving condition READY.
ABS and ESP ®
are unavailable due to a fault. Therefore BAS, BAS PLUS, COL-
LISION PREVENTION ASSIST PLUS, EBD, PRE ‑SAFE®
, PRE‑SAFE ®
PLUS,
PRE‑SAFE ®
Brake, HOLD function, hill start assist, ESP ®
trailer stabilisation,
crosswind driving assistance, adaptive brake lights, STEER CONTROL, Active Lane Keeping Assist and Active Blind Spot Assist are also unavailable.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions
listed above. The front and rear wheels could therefore lock, for example, if you
brake hard.
The steerability and braking characteristics may be severely affected. The
braking distance may increase in an emergency braking situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Observe the additional display messages in the multifunction display.
X Drive on carefully.
X Visit a qualified specialist workshop. ÷
N
The yellow ESP ®
warning lamp flashes while the vehicle is in motion.
ESP ®
or traction control has intervened because there is a risk of skidding or
at least one wheel has started to spin.
Cruise control or DISTRONIC PLUS is deactivated.
X Only depress the accelerator pedal as far as necessary when pulling away.
X Accelerate more gently while the vehicle is in motion.
X Adapt your driving style to suit the road and weather conditions.
X Do not deactivate ESP ®
.
In rare cases (Y page 81), it may be best to deactivate ESP ®
.
Observe the important safety notes on ESP ®
(Y page 80). Warning and indicator lamps in the instrument cluster
357On-board computer and displays Z