Mercedes C-Class Start Stop Not Working

Mercedes C-Class Start Stop Not Working

The Mercedes-Benz C-Class ECO start stop system is designed to switch off the engine every time the vehicle comes to a stop (auto-stop) and to quickly restart when the driver intends on moving off. This function helps to save fuel and reduces exhaust emissions. A robust starter motor and secondary battery has been implemented to ensure longevity and reliability. Symbols help to determine the status of the stop start system:

  • Green: conditions for auto-stop have been met and engine will be shut down when the vehicle stops Mercedes C-Class Start Stop Ready.
  • Yellow: ECO start stop is active, but conditions are not met Mercedes C-Class Start Stop Conditions Not Met.
  • No ECO symbol displayed: ECO start stop is switched off or has been deactivated due to a fault with the system.

Mercedes C-Class ECO Start Stop Conditions

If your Mercedes C-Class start stop is not working and the engine fails to switch off when the vehicle comes to a stop, it’s likely that one of the conditions that the system checks prior to auto-stop has not been met. These conditions are:

  • Engine coolant is at optimal operating temperature; greater than 60°C, less than 115°C.
  • Transmission oil temperature greater than 10°C, less than 120°C.
  • Gears range is in either ‘Drive’ or ‘Neutral’.
  • The bonnet / hood is closed.
  • The driver’s door is closed.
  • The driver’s seat belt is fastened.
  • There is sufficient vacuum in the brake booster. Vehicle may restart if there’s a vacuum change whilst stopped.
  • Vehicle has not stopped on a slope of more than 15% (Hill Start Assist is not active).
  • High current draw, for example windscreen wipers, demister, defroster all on at the same time may prevent auto-stop.
  • ABS is not active.
  • The battery temperature is not too low or high, typically between 5°C (41°F) to 60°C (140°F).
  • Steering wheel angle in the specified range, typically less than 90° from the center position.
  • The vehicle may restart if the steering wheel is operated during auto-stop.
  • Interior temperature is within an acceptable level based on the preset values of the AC system.
  • The ambient temperature should be less than 35°C (95°F).
  • Demist or defrost is not selected.
  • Battery and charging system voltage is greater than 11.3 volts.
  • Temperature of the catalytic converter not too high.
  • Diesel particulate filter (DPF) is not being regenerated.

Switching off the Mercedes C-Class Start Stop

If you wish to switch off the Mercedes C-Class ECO start stop system, locate the button with the start stop symbol Mercedes-Benz C-Class ECO Start Stop (Auto-stop) Warning Light or ‘ECO’ button. Depending on your model of C-Class, the button is located wither on the centre console or the dashboard. The ECO start stop system can only be turned off for the engine start / key cycle only and not permanently.

More about the Mercedes C-Class
Link Mercedes C-Class Dashboard Warning Lights
Link Mercedes C-Class Start Stop Not Working
Link Mercedes C-Class Tyre Pressure Reset
Link Mercedes C-Class Key Battery Change