Tech Session – Richard Simonds

How Your Mercedes-Benz Communicates With You

How urgent are the messages on your instrument cluster or center console?

Over the past 15 years, Mercedes-Benz has added a number of safety features that warn drivers of dangerous situations – in the vehicle’s operation and on the road. The big question is: Do you know what these warnings mean and how to respond?

The check-engine light illuminates: Should you pull off the road immediately and turn off the engine, go straight to your service adviser for a check-up or simply wait until your next service appointment? 

A warning message appears in the multifunction display in the center of the speedometer with text in red: What should you do?

The brake-warning lamp illuminates: Should you just release the parking brake or go straight to your service adviser to check if there is a serious malfunction in the brake system?

The most important point to remember: Messages in text and symbols illuminated red are of high urgency needing immediate attention; message text and symbols in yellow are moderate to low urgency needing attention as soon as possible.

WARNING LIGHTS

LEFT DIAL, CLOCKWISE FROM LEFT: Tire Pressure Monitoring; ESP Off; ESP; Distance Warning; Power Steering; Restraint System; Seat Belt; Low Fuel Warning. If ESP – Electronic Stability Program – light is yellow while engine is running, it can mean a malfunction in safety systems.

RIGHT DIAL, CLOCKWISE FROM LEFT: Electric Parking Brake – if yellow, indicates malfunction or low voltage; ABS warning; Check Engine; PARK – indicates Parking Brake is set; BRAKE – if illuminated, indicates malfunction or low brake fluid level; Coolant – if illuminated, indicates engine is running too hot.

High-urgency messages

Battery symbol and message illuminated in red when driving:

1. Get off the road and stop the engine as soon as possible;

2. Check the Poly-V belt between the radiator and engine, under the hood. If you are not sure about the belt, do not drive the car with low or no electrical power;

3. Have the vehicle towed to your authorized Mercedes-Benz Center to diagnose the cause(s).

Coolant symbol is red when driving:

1. Get off the road and stop the engine as soon as possible;

2. Let radiator coolant and engine cool– approximately 30 minutes;

3. Wearing protective gloves or using a towel to avoid being scalded, carefully remove cap on radiator or coolant reservoir and add water slowly with engine idling if fluid level is low;

4. If coolant symbol remains red while engine is running, get the car towed to an authorized Mercedes-Benz Center.

Engine-oil symbol illuminated in red: This symbol will come on intermittently when the car is one quart low on oil and will stay on when more oil is depleted. A message “Add 1 Qt. engine oil at next refueling” will appear in the center of the speedometer.

1. Check for oil leaks below engine where the car is regularly parked;

2. Replace lost oil and monitor for loss if symbol and message reappear.

Moderate-urgency messages

ABS/ESP/Brake/Brake Assist symbols in instrument cluster are yellow: (note that with mbrace, mbrace2 or TeleAid, the wrench button can be pressed for technical assistance and the problems may be solved immediately)

1. Drive very carefully because vehicle control systems for brakes are deactivated;

2. Visit authorized Mercedes-Benz Center soon to diagnose the cause(s).

Check-engine light in instrument cluster:

1. Check that the fuel cap is on tight and restart engine two to three times to reset the warning light;

2. Limp-home mode may be activated;

3. Visit your authorized Mercedes-Benz Center as soon as possible to diagnose the cause(s).

Tire-pressure monitoring-system symbol is on:

1. Get off the road and stop the car where you can walk around and check tire pressure visually, or preferably with a gauge;

2. If a tire is low, add air to the correct pressure; the light will go out after a few minutes of driving;

3. Go to your authorized Mercedes-Benz Center to determine why the tire is losing pressure. Slow leaks can become major leaks or blowout risks in very little time. Some new models have run-flat type tires (MOExtended) and you can drive up to 50 mph for up to 50 miles lightly loaded or 18 miles fully loaded before changing the tire.

Low-urgency messages

Passenger airbag deactivated message in center of speedometer: (signals that the passenger airbag will not deploy in a collision)

1. Stop in a safe location, turn off the ignition and have the passenger get out of the vehicle;

2. Raise the seat bottom to check for objects underneath that may affect the sensors;

3. Remove any objects from under the seat and lower it back to its regular position;

4. With the seat unoccupied, turn on the ignition and wait 60 seconds for the system to perform its check cycles;

5. If the message does not turn off when driving, drive carefully until you can have it inspected;

6. Visit your authorized Mercedes-Benz Center as soon as possible to diagnose the cause(s).

Supplemental Restraint System (SRS) Service Required message in multifunction display: (indicates the airbag or emergency tensioning device may either be triggered unintentionally or may not deploy in a collision)

1. Visit your authorized Mercedes-Benz Center as soon as possible to diagnose the cause(s).

Daytime running lights symbol in the instrument cluster indicates headlights on at half-power when the engine is running:

Remember that daytime running lights are not the same as having full-power headlights on with taillights, running lights and side-marker lights (often required by state law when using your wipers).

This list represents only a selection of the most serious safety messages your Mercedes-Benz may display. Don’t rely only on this information: Be sure to read your Operator/Owner’s Manual – especially for newer-year models – to understand the many ways your vehicle can communicate with you about potentially serious problems needing your attention.