CLS - Interactive Owner's Manual [In depth | Practical advice

Points to remember

Risk of accident and injury

Always have maintenance work carried out at a qualified specialist workshop which has the necessary specialist knowledge and tools to carry out the work required.

Mercedes-Benz recommends that you use a Mercedes-Benz Service Centre for this purpose.

In particular, work relevant to safety or on safety-related systems must be carried out at a qualified specialist workshop. If this work is not carried out correctly, the operating safety of your vehicle could be compromised. There is a risk of accident and injury.

Indicator and warning lamps in switches and buttons

Problem

Possible cause/consequence

Suggested solutions

One or all of the indicator lamps in the seat ventilation* button are flashing.

There is insufficient voltage because too many consumers are switched on. The seat ventilation* has switched itself off automatically.

	Switch off consumers that are not required, e.g. reading lamps, interior lighting, etc.
	The seat ventilation* will automatically switch back on as soon as there is sufficient voltage again.

One or all of the indicator lamps in the seat heating* button are flashing.

There is insufficient voltage because too many consumers are switched on. The seat heating* has switched itself off automatically.

	Switch off consumers that are not required, e.g. reading lamps, interior lighting, etc.
	The seat heating* will automatically switch back on as soon as there is sufficient voltage again.

The steering wheel heating* indicator lamp on the lower left lever of the steering column is flashing.

There is insufficient voltage because too many consumers are switched on. The steering wheel heating* has switched itself off automatically.

	Switch off consumers that are not required, e.g. reading lamps, interior lighting, etc.
	The steering wheel heating* will automatically switch back on as soon as there is sufficient voltage again.

The indicator lamp in the resources/font_symbols/mbsymb3/mbsymb3_0032.png button on the Thermatic/4‑zone Thermotronic* control panel flashes three times when you press the button. The cooling system cannot be switched on.

Cooling has been deactivated due to a malfunction.

Visit a qualified specialist workshop.

The indicator lamp in the resources/font_symbols/mbsymb3/mbsymb3_00af.png rear-window heating button is flashing. The rear-window heating has switched itself off prematurely or cannot be switched on.

There is insufficient voltage because too many consumers are switched on.

	Switch off consumers that are not required, e.g. reading lamps, interior lighting, etc.
	The rear-window heating will automatically switch back on as soon as there is sufficient voltage again.

Vehicles with automatic child seat recognition on the front-passenger seat*:

The resources/font_symbols/mbsymb1b/mbsymb1b_0035.png PASSENGER AIRBAG OFF warning lamp on the centre console is lit.

A special Mercedes-Benz child seat with automatic child seat recognition has been fitted to the front-passenger seat. The front-passenger airbag has therefore been disabled.

Vehicles with automatic child seat recognition on the front-passenger seat*:

The resources/font_symbols/mbsymb1b/mbsymb1b_0035.png PASSENGER AIRBAG OFF warning lamp on the centre console is lit.

Risk of injury

There is no child seat fitted to the front-passenger seat. The automatic child seat recognition* is malfunctioning.

Remove electronic equipment from the front-passenger seat, e.g.:

Notebooks
Mobile phones
Cards with transponders, e.g. ski passes or access passes

If the resources/font_symbols/mbsymb1b/mbsymb1b_0035.png PASSENGER AIRBAG OFF warning lamp is still lit:

Visit a qualified specialist workshop.

Indicator and warning lamps in the instrument cluster

Problem

Possible cause/consequence

Suggested solutions

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The yellow ABS warning lamp comes on while the engine is running.

Risk of accident

ABS is unavailable due to a malfunction. Therefore, Brake Assist, ESP®, EBV and PRE-SAFE® are, for example, also deactivated.

The brake system continues to function normally, but without electronic support. The wheels could therefore lock if you brake hard, for example.

	Drive on carefully.
	Observe the additional messages in the multi-function display more.
	Visit a qualified specialist workshop as soon as possible.

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The yellow ESP® warning lamp is lit while the engine is running.

Risk of accident

ESP® is deactivated. ESP® will not stabilise the vehicle if it starts to skid or if a wheel starts to spin.

Reactivate ESP® more.

Exceptions: more.

Adapt your driving style to suit the road and weather conditions.

The yellow ESP® warning lamp is lit while the engine is running.

Risk of accident

ESP® is unavailable due to a malfunction. ESP® will not stabilise the vehicle if it starts to skid or if a wheel starts to spin.

	Observe the additional messages in the multi-function display more.
	Drive on carefully.
	Visit a qualified specialist workshop.

The yellow ESP® warning lamp flashes while the vehicle is in motion.

Risk of accident

ESP® or traction control has intervened because at least one wheel has started to spin.

Cruise control or Distronic* is deactivated.

	Only depress the accelerator pedal as far as necessary when pulling away.
	Release the accelerator pedal while you are driving.
	Adapt your driving style to suit the road and weather conditions.
	Do not deactivate ESP®. Exceptions: more.

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The red brake system warning lamp comes on while you are driving. You will also hear a warning tone.

You are driving with the parking brake applied.

	Release the parking brake.
	The warning lamp goes out and the warning tone ceases.

The red brake system warning lamp comes on while the engine is running. You will also hear a warning tone.

Risk of accident

There is insufficient brake fluid in the fluid reservoir.

	Do not continue driving under any circumstances.
	Consult a qualified specialist workshop immediately.
	Observe the additional messages in the multi-function display more.
	Under no circumstances should you top up the brake fluid. This will not rectify the fault.

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The red distance warning lamp* lights up while the vehicle is in motion.

Risk of accident

The distance to the vehicle in front is too short for the speed selected.

Increase the distance.

The red distance warning lamp* lights up while the vehicle is in motion. You will also hear a warning tone.

Risk of accident

You are approaching a vehicle in front at too great a speed or Distronic* has detected a stationary obstacle in your line of travel.

	Be prepared to brake immediately.
	Pay careful attention to the traffic situation. You may have to brake or take evasive action.

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The red coolant warning lamp comes on while the engine is running.

There is insufficient coolant in the expansion tank.

The coolant is too hot and the engine is no longer being cooled sufficiently.

	Stop the vehicle as soon as possible. Pay attention to the traffic conditions as you do so.
	Allow the engine and coolant to cool.
	Check the coolant level. Observe the warning notes more. Top up the coolant if necessary.
	Have the coolant system checked at a qualified specialist workshop if the coolant needs topping up more often than usual.

The red coolant warning lamp comes on while the engine is running.

If the coolant level is correct, the radiator fan may be faulty.

The coolant is too hot and the engine is no longer being cooled sufficiently.

	If the coolant temperature is less than 120, you can continue driving to the nearest qualified specialist workshop.
	In doing so, avoid heavy loads on the engine (e.g. driving in mountainous terrain) and stop-and-go driving.

The red coolant warning lamp comes on while the engine is running. You will also hear a warning tone.

The coolant level is too low.

The coolant temperature has exceeded 120 resources/font_symbols/CorpoSWGL/CorpoSWGL_2020.png . The engine is not being cooled sufficiently and may be damaged.

	Stop the vehicle as soon as possible. Pay attention to the traffic conditions as you do so.
	Allow the engine and coolant to cool.
	Check the coolant level. Observe the warning notes more. Top up the coolant if necessary.
	Have the coolant system checked at a qualified specialist workshop if the coolant needs topping up more often than usual.

The red coolant warning lamp comes on while the engine is running. You will also hear a warning tone.

If the coolant level is correct, the radiator fan may be faulty.

The coolant temperature has exceeded 120 resources/font_symbols/CorpoSWGL/CorpoSWGL_2020.png . The engine is not being cooled sufficiently and may be damaged.

	Do not continue driving under any circumstances.
	Consult a qualified specialist workshop.

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The yellow engine diagnostics warning lamp comes on while the engine is running.

Vehicles with a diesel engine: the fuel tank has run dry.

	Start the engine three to four times after refuelling.
	Emergency running mode is cancelled. The vehicle need not be checked.

The yellow engine diagnostics warning lamp comes on while the engine is running.

There may be a malfunction:

in the fuel injection system
in the exhaust system
in the ignition system (on vehicles with a petrol engine)

The emission limit values may be exceeded and the engine may be running in emergency mode.

Have the vehicle checked as soon as possible at a qualified specialist workshop.

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The yellow tyre pressure monitor* warning lamp is on.

Risk of accident

The tyre pressure monitor* has detected a sudden or significant pressure loss in at least one of the tyres.

	Stop the vehicle without making any sudden steering or braking manoeuvres. Pay attention to the traffic conditions as you do so.
	Observe the additional messages in the multi-function display more.
	The warning light will go out after the flat tyre has been changed and you have been driving for a few minutes.

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The red SRS warning lamp is lit while the engine is running.

Risk of injury

The restraint systems are faulty. The airbags or belt tensioners may either be triggered unintentionally or, in the event of an accident, not be triggered at all.

Visit a qualified specialist workshop immediately.

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The red seat belt warning lamp lights up for 6 seconds after the engine starts up

(Only for certain countries.)

.

The seat belt warning lamp reminds the driver and front passenger to fasten their seat belts.

Fasten your seat belt more.

After the engine starts you will hear a warning tone for up to 6 seconds.

Risk of injury

The driver's seat belt is not fastened.

	Fasten your seat belt more.
	The warning tone ceases.

The red seat belt warning lamp lights up after starting the engine, as soon as the driver's door or the front-passenger door is closed.

Risk of injury

The driver or front passenger has not fastened their seat belt.

	Fasten your seat belt more.
	The warning lamp goes out.

Risk of injury

There are objects on the front-passenger seat.

	Remove the objects from the front-passenger seat and stow them safely.
	The warning lamp goes out.

The red seat belt warning lamp flashes and you hear an intermittent warning tone.

Risk of injury

The driver or front passenger has not fastened their seat belt and you are driving faster than 25 km/h or have driven faster than 25 km/h for a short time.

	Fasten your seat belt more.
	The warning lamp goes out and the intermittent warning tone ceases.

Risk of injury

There are objects on the front-passenger seat and you are driving faster than 25 km/h or have driven faster than 25 km/h for a short time.

	Remove the objects from the front-passenger seat and stow them safely.
	The warning lamp goes out and the intermittent warning tone ceases.

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The yellow reserve fuel warning lamp comes on while the engine is running.

The fuel level has fallen below the reserve range. The operation of the auxiliary heating* can no longer be guaranteed.

Refuel at the nearest filling station.

Warning tones

Problem

Possible cause/consequence

Suggested solutions

The anti-theft alarm system* is suddenly triggered.

You have opened the vehicle using the emergency key element without deactivating the anti-theft alarm system* first.

Switch off the alarm more.

You hear a warning tone.

A message appears in the multi-function display.

See the explanations for the display message more.

You hear a warning tone.

You are driving with the parking brake applied.

Release the parking brake.

You hear a warning tone.

You have opened the driver's door and forgotten to switch off the lights.

Turn the light switch to resources/font_symbols/mbsymb1/mbsymb1_004d.png or .

You hear a warning tone.

Risk of injury

The driver or front passenger has not fastened their seat belt.

Fasten your seat belt more.

You hear a continuous tone.

You have switched off the engine and opened the bonnet or the driver's door with Hold activated.

Deactivate HOLD more.

Accident

Problem

Possible cause/consequence

Suggested solutions

Fuel is leaking from the vehicle.

Risk of fire

The fuel line or the fuel tank has been damaged.

	Switch off the ignition immediately.
	Remove the ignition key.
	Do not restart the engine under any circumstances.

The leaking fuel creates a risk of fire or explosion.

Consult a qualified specialist workshop.

You are unable to determine the extent of the damage.

Consult a qualified specialist workshop.

You cannot detect any damage.

Start the engine as normal.

The NECK-PRO head restraints on the driver's and front-passenger seats have been triggered.

Your vehicle has been involved in a rear-end collision.

Reset the NECK-PRO head restraints more.

Fuel and fuel tank

Problem

Possible cause/consequence

Suggested solutions

Fuel is leaking from the vehicle.

Risk of fire

The fuel line or the fuel tank is defective.

	Turn the key to position 0 in the ignition lock immediately and remove it.
	Do not restart the engine under any circumstances.

The leaking fuel creates a risk of fire or explosion.

Consult a qualified specialist workshop.

The fuel filler flap cannot be opened.

The fuel filler flap is not released.

Unlock the vehicle more.

The opening mechanism is jammed.

Consult a qualified specialist workshop.

The fuel tank has been run completely dry on a vehicle with a diesel engine.

There is air in the fuel system.

	Refuel the vehicle.
	Switch on the ignition for approximately 10 seconds (key in position 2 in the ignition lock).
	Start the engine continuously for up to 40 seconds until it runs smoothly.
	The fuel system is now free of air.

If the engine does not start:

	Wait two minutes.
	Repeat the starting procedure for up to 40 seconds.

If the engine still does not start:

Consult a qualified specialist workshop.

Engine

Problem

Possible cause/consequence

Suggested solutions

The engine will not start.

HOLD is activated.

	Deactivating HOLD more.
	Start the engine again.

The engine will not start. You can hear the starter motor operating.

There may be a malfunction in the engine electronics.
There may be a malfunction in the fuel supply.

	Turn the key back to position 0 in the ignition lock before the next starting attempt.
	Try to start the engine again more. When doing so, remember that excessively long and frequent attempts to start the engine will drain the battery.

If the engine does not start after several attempts:

Consult a qualified specialist workshop.

Vehicles with a diesel engine:

The engine will not start. You can hear the starter motor operating. The reserve fuel warning lamp is on and the fuel gauge shows 0.

The fuel tank has been run dry.

	Refuel the vehicle.
	Bleed the fuel system more.

The engine will not start. You cannot hear the starter motor operating.

The on-board voltage is too low because the starter battery is too weak or discharged.

Jump-start the vehicle more.

If the engine does not start despite attempting to jump-start it:

Consult a qualified specialist workshop.

Vehicles with a petrol engine:

The engine is not running smoothly and is misfiring.

The engine electronics or a mechanical component of the engine control unit have been damaged.

	Only depress the accelerator pedal slightly.
	Have the cause rectified immediately at a qualified specialist workshop.
	Otherwise, non-combusted fuel may get into the catalytic converter and damage it.

A coolant temperature of over 120 °C is displayed. The coolant warning lamp may also be on and a warning tone may sound more.

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 cool down.
	Check the coolant level more. Observe the warning notes as you do so and top up the coolant if necessary.

If the coolant level is correct, the radiator fan may be faulty. The coolant is too hot and the engine is no longer being cooled sufficiently.

	If the coolant temperature is less than 120°C, you can continue driving to the nearest qualified specialist workshop.
	Avoid heavy loads on the engine as you do so, e.g. when driving on mountain roads and stop/start driving.

Automatic transmission

Problem

Possible cause/consequence

Suggested solutions

The transmission has problems shifting gear

The transmission is losing oil.

Have the transmission checked at a qualified specialist workshop immediately.

The acceleration ability is deteriorating.

The transmission no longer changes gear.

The transmission is in emergency mode.

It is only possible to shift into 2nd gear and reverse gear.

	Stop the vehicle.
	Move the selector lever to P.
	Turn the key to position 0 in the ignition lock.
	Wait at least 10 seconds before restarting the engine.
	Move the selector lever to position D or R.
	If D is selected, the transmission shifts into 2nd gear; if R is selected, the transmission shifts into reverse gear.
	Have the transmission checked at a qualified specialist workshop immediately.

Parktronic*

Problem

Possible cause/consequence

Suggested solutions

Only the red segments in the Parktronic warning display are lit. You also hear a warning tone for approximately two seconds.

Parktronic is deactivated after approximately 20 seconds and the indicator lamp in the Parktronic button lights up.

Parktronic has malfunctioned and has switched itself off.

If problems persist, have Parktronic checked at a qualified specialist workshop.

Only the red segments in the Parktronic warning display are lit. Parktronic is deactivated after approximately 20 seconds.

The Parktronic sensors are dirty or there is interference.

	Clean the Parktronic sensors more.
	Switch the ignition back on.

Only the red segments in the Parktronic warning display are lit. Parktronic is deactivated after approximately 20 seconds.

The problem may be caused by an external source of radio or ultrasound waves.

See if Parktronic functions in a different location.

Headlamps and turn signals

Problem

Possible cause/consequence

Suggested solutions

The headlamps or the turn signals in the exterior mirrors are misted up on the inside.

Air humidity is very high.

	Drive with the headlamps switched on.
	The headlamps are demisted after a short distance.

The headlamp housing is not sealed and moisture has been able to enter.

Have the headlamps checked at a qualified specialist workshop.

Windscreen wipers

Problem

Possible cause/consequence

Suggested solutions

The windscreen wipers are jammed.

Leaves or snow, for example, may be obstructing the windscreen wiper movement. The wiper motor has been deactivated.

	For safety reasons, you should remove the key from the ignition lock.
	Remove the cause of the obstruction.
	Switch the windscreen wipers back on.

The windscreen wipers fail completely.

The windscreen wiper drive is malfunctioning.

	Select another wiper speed on the combination switch.
	Have the windscreen wipers checked at a qualified specialist workshop.

Windows

Problem

Possible cause/consequence

Suggested solutions

A side window will not close.

An object is blocking the side window and preventing it from closing.

	Remove the object(s).
	Close the side window.

You cannot see the cause.

Close the side window with increased force or without the anti-entrapment feature more.

Mirrors

Problem

Possible cause/consequence

Suggested solutions

An exterior mirror has been pushed out of position.

Vehicles with exterior mirrors that cannot be folded in/out electrically:

Push the mirror into the correct position manually.

Vehicles with electrically folding exterior mirrors*:

	Press the mirror-folding button* more repeatedly until you hear a distinct click.
	The mirror housing is engaged again and you can adjust the mirror as usual more.

Key

Problem

Possible cause/consequence

Suggested solutions

You cannot lock or unlock the vehicle using the key.

The key batteries are discharged or nearly discharged.

Point the tip of the key at the driver's door handle from close range and try to open the vehicle again.

If this does not work:

	Lock or unlock the vehicle using the emergency key element more.
	Check the key batteries more and replace them if necessary more.

The key is faulty.

	Lock or unlock the vehicle using the emergency key element more.
	Have the key checked at a qualified specialist workshop.

The battery charge indicator lamp of the key does not go on during the test.

The key batteries are discharged.

Change the batteries more.

You have lost a key.

	Have the key cancelled at a Mercedes-Benz Service Centre.
	Report the loss immediately to the vehicle insurers.
	If necessary, have the manual locks changed too.

You have lost the emergency key element.

	Report the loss immediately to the vehicle insurers.
	If necessary, have the manual locks changed too.

The key cannot be turned in the ignition lock.

The key has been in position 0 for a considerable time.

	Remove the key and reinsert it into the ignition lock.
	Check the starter battery and recharge it if necessary more.
	Start the engine.

The on-board voltage is too low.

Switch off non-essential consumers, e.g. seat heating* or interior lighting, and try to turn the key again.

If this does not work:

	Check the starter battery and recharge it if necessary more.
or
	Jump-start the vehicle more.
or
	Consult a qualified specialist workshop.

KEYLESS GO*

Problem

Possible cause/consequence

Suggested solutions

You cannot lock or unlock the vehicle using the KEYLESS GO key.

The KEYLESS GO key batteries are discharged or nearly discharged.

Lock or unlock the vehicle using the remote control function of the key. Point the tip of the key at the driver's door handle from close range and try to open the vehicle again.

If this does not work:

	Lock or unlock the vehicle using the emergency key element more.
	Check the KEYLESS GO key batteries more and replace them if necessary more.

There is a fault with KEYLESS GO.

	Lock or unlock the vehicle using the remote control function of the key. To do this, point the tip of the key at the driver's door handle from close range and try to open the vehicle again.
	Have the KEYLESS GO key checked at a qualified specialist workshop.

There is interference from a powerful source of radio waves.

Lock or unlock the vehicle using the emergency key element more.

The battery check lamp in the KEYLESS GO key does not light up when tested.

The KEYLESS GO key batteries are discharged.

Change the batteries more.

The vehicle cannot be started using the KEYLESS GO key and the KEYLESS GO button. The KEYLESS GO key is in the vehicle.

A door is open. The key therefore cannot be detected so easily.

Close the door and try to start the vehicle again.

You did not depress the brake when starting the engine.

Depress the brake and press the KEYLESS GO button.

There is interference from a powerful source of radio waves.

Start your vehicle using the KEYLESS GO key in the ignition lock.

You have lost the KEYLESS GO key.

	Have the KEYLESS GO key cancelled at a Mercedes-Benz Service Centre.
	Report the loss immediately to the vehicle insurers.
	If necessary, have the manual locks changed too.

Auxiliary heating/ventilation*

Problem

Possible cause/consequence

Suggested solutions

The auxiliary heating is not working.

The fuel level is down to the reserve level.

Refuel at the nearest filling station.

The battery is not sufficiently charged.

Charge the battery.

The auxiliary heating is faulty.

Have the auxiliary heating checked at a qualified specialist workshop.

The auxiliary heating cannot be switched on or off using the remote control.

The remote control display shows FAIL and the resources/font_symbols/mbsymb3/mbsymb3_00a2.png symbol.

The signal transmission between the remote control and the vehicle is faulty.

	Change your position in relation to the vehicle, moving closer if necessary.
	Make another attempt to switch the auxiliary heating on or off using the remote control.

The remote control display shows FAIL and the resources/font_symbols/mbsymb3/mbsymb3_00a1.png symbol.

There is not enough fuel in the tank, or the auxiliary heating is faulty.

	Refuel at the nearest filling station.
	Have the auxiliary heating checked at a qualified specialist workshop.

Parking up the vehicle

Problem

Possible cause/consequence

Suggested solutions

The vehicle is to be left parked up for longer than six weeks.

	Visit a qualified specialist workshop and seek advice.
	Disconnect the battery more.

Troubleshooting

Points to remember

Indicator and warning lamps in switches and buttons

Indicator and warning lamps in the instrument cluster

Warning tones

Accident

Fuel and fuel tank

Engine

Automatic transmission

Parktronic*

Headlamps and turn signals

Windscreen wipers

Windows

Mirrors

Key

KEYLESS GO*

Auxiliary heating/ventilation*

Parking up the vehicle