Start Stop in Mercedes Vehicles
The Start-Stop system is a pivotal innovation in modern Mercedes vehicles, designed to enhance fuel efficiency and reduce emissions. This article delves into the functionality, benefits, common issues, and maintenance tips for the Start and Stop system, ensuring you get the most out of this advanced feature.
Overview and Functionality
The Start and Stop system automatically shuts off the engine when the vehicle is stationary, such as at traffic lights, and restarts it when the driver is ready to move again. This reduces idle time, conserving fuel and lowering emissions. Mercedes has integrated this system seamlessly into their vehicles, using advanced sensors and technology to ensure a smooth transition between stopping and starting.
Benefits and Efficiency
One of the primary benefits of the Start and Stop system is improved fuel efficiency. By reducing the amount of time the engine spends idling, fuel consumption is significantly lowered, leading to cost savings for the driver. Additionally, this system helps in reducing the vehicle’s carbon footprint by cutting down on emissions.
Common Issues and Troubleshooting
While the Start and Stop system is generally reliable, some common issues may arise. These can include the system not activating, the engine failing to restart promptly, or the system turning off unexpectedly. Troubleshooting tips include checking the battery, ensuring the vehicle’s systems are up to date, and consulting the vehicle’s manual. Persistent issues may require professional diagnostics.
Why is my Mercedes engine stop start not working?
How does the start-stop function work?
When the vehicle is at a standstill, the START-STOP function automatically stops the engine and restarts it as soon as the driver wants to move off by releasing the brake pedal (Mercedes A-Class W176 equipped with a 7-speed dual-clutch gearbox 7G-DCT) and pressing the clutch pedal (A-Class equipped with a manual gearbox Mercedes Benz A-Class). Cutting off the engine when the vehicle is stationary reduces fuel consumption by up to 15% and reduces exhaust gas emissions and noise emissions.
Conventional engine shutdown and startup with the ignition switch or via the start-stop switch are still possible. The engine management control unit continuously diagnoses the engine management system and evaluates the system states for the START-STOP function.
When the operating conditions are met, the driver is informed of the activation of the START AND STOP function by displaying the “ECO” symbol on the multifunction display in the instrument cluster.
What conditions are needed before the stop-start system functions?
Among the necessary conditions for the operation of the START-STOP function, we can distinguish:
- Battery must be charged (High State Of Charge, SOC)
- Engine restart
- Outside temperature within the range of: -10°C < Temperature < 40°C
- Engine management system diagnostic completed and without any faults
- Exceeding the speed limit by 8 km/h once in forward motion
- Exceeding the speed limit by 15 km/h once in forward motion after executing a maneuver.
These conditions ensure optimal functionality and safety when utilizing the START AND STOP feature.
What triggers auto start-stop?
The engine shuts off automatically at a red light if all of the following operating conditions are met:
- The control indicator for the start-stop function (ECO) illuminates (the system is without faults, and the start-stop function is activated).
- Vehicle speed = 0 km/h (if equipped with a 7-speed dual-clutch gearbox 7G-DCT) or < 8 km/h (if equipped with a manual gearbox Mercedes Benz Class A).
- Engine coolant temperature is >20°C.
- Engine speed within theoretical range.
- Gearbox oil temperature is above 10°C and below 120°C (if equipped with a 7-speed dual-clutch gearbox 7G-DCT).
- Gear lever in “D” or “N” position (if equipped with an automatic dual-clutch gearbox).
- Gear lever in neutral position (if equipped with a manual gearbox).
- Clutch pedal not depressed (if equipped with a manual gearbox).
- Accelerator pedal not depressed.
- Brake pedal depressed (if equipped with a manual gearbox).
- Service brake applied until the vehicle comes to a stop (if equipped with a 7-speed dual-clutch gearbox 7G-DCT).
- Engine hood closed.
- No accident signal.
- Driver’s door closed.
- Driver’s seat belt fastened.
- Balanced interior temperature.
How does an auto stop-start restart?
With a manual gearbox, the engine automatically restarts when the clutch pedal is depressed and the accelerator pedal is pressed.
With a 7-speed dual-clutch gearbox 7G-DCT, the engine starts automatically when the brake pedal is released or the accelerator pedal is pressed.
The engine management control unit commands the starter and fuel pump => the engine starts.
Case Study : Why is my Mercedes auto start stop not working? Mercedes A-Class
Why does start-stop only work sometimes?
Based on the operational and functional conditions of the Mercedes Classe A’s START AND STOP system, potential causes of system failure could include:
- Defective auxiliary start-stop battery (located on the passenger side under the glove compartment).
- Defective 12V AGM onboard network battery (located in the engine compartment on the right).
- Low battery voltage.
- Non-compliant battery (EFB and AGM batteries are recommended).
- Battery charging issues due to a faulty alternator.
- Modifications to electrical accessories.
- Low fuel level.
- Failure to meet the aforementioned prerequisites (e.g., excessively high outside temperature).
- Failure to reset the battery after replacement.
How to permanently disable auto start-stop Mercedes?
You can deactivate it through the following steps:
There is a Start and Stop deactivation button on the dashboard of your vehicle. See the image below start stop button for mercedes N72/1s50.
You can use this button to deactivate your Start-Stop function each time you start the vehicle. Note that this procedure requires you to repeat the process each time you start the vehicle.
Important note : You must to know
I would advise against completely deactivating the Start-Stop function in order to retain its benefits, such as fuel savings and reduced exhaust emissions, to help preserve our planet.
However, if you are determined to deactivate this function, there is a simple procedure:
Create an electrical bridge behind the Start and Stop activation button. This will keep the button engaged at all times, thus completely deactivating the Start and Stop function.