What is the Start-Stop System?
The start-stop system is a fuel-saving technology employed by many modern vehicles, including those manufactured by Audi and Volkswagen (VW). This system automatically shuts off the engine when the vehicle comes to a complete stop and restarts it when the driver is ready to move again. This feature is particularly beneficial in reducing fuel consumption and emissions during idle times, such as at traffic lights or in heavy traffic.
The constant engine starting and stopping does also put a strain on your starter motor, and the whole system requires more complex air conditioning and power steering pumps (electronically actuated). For many people these complexities just introduce more points of potential mechanical or electrical failure.
How Does the Start-Stop System Work?
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Engine Control Unit (ECU): The brain behind the start-stop system is the ECU, which monitors various parameters like vehicle speed, engine temperature, battery charge, and brake pedal position to decide when to activate the system.
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Automatic Shutoff: When the vehicle stops, the ECU shuts off the engine if certain conditions are met (e.g., engine is warm, battery charge is sufficient, and the air conditioning system is not in heavy use).
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Automatic Restart: Once the brake pedal is released or the clutch is engaged (in manual transmission vehicles), the ECU sends a signal to restart the engine seamlessly.
Benefits of the Start-Stop System
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- Fuel Economy: Reduces fuel consumption by shutting off the engine during idle periods. Studies have shown that start-stop systems can improve fuel economy by 5-10% in city driving conditions (Clore Automotive)
- Reduced Emissions: Helps lower the vehicle’s emissions by reducing idle time. The system can lead to a reduction in CO2 emissions by up to 5-7% (Clore Automotive).
- Engine Wear and Tear: Modern start-stop systems are designed to handle frequent starts and stops, potentially extending engine life with less overall wear compared to traditional systems.
Disabling the Start-Stop System Using Carista OBD2 Scanner
Despite the benefits, some drivers may find the start-stop system inconvenient or prefer to have more control over their vehicle. Disabling this system can be quickly and easily done using an OBD2 (On-Board Diagnostics) scanner. Here’s how:
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Check vehicle compatibility & Acquire Carista OBD2 Scanner: Ensure you have a compatible OBD2 scanner for your Audi or VW. Check Vehicle compatibility
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Locate the OBD2 Port: Typically found under the dashboard near the steering column.
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Connect the Scanner: Plug the OBD2 scanner into the port and turn on the vehicle’s ignition without starting the engine.
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Download Carista app from Google Play or the App Store
- Open the Carista OBD App and go to the ''Customize'' menu -> Chassis & Engine
- Test the Vehicle: Click on Disable. Restart the vehicle to ensure the start-stop system is disabled. The engine should no longer shut off automatically when the vehicle stops.
Specific Audi and VW Models
Audi MLB Cars (A4 B8, A6 C7 and Derivatives)
You can easily disable the start-stop system on these models with just a few taps. There is an option to set the car to remember the last state of the start-stop system, which, by default, deactivates the system. If turned off, it remains off even after the ignition is turned off and back on again. These settings can be found in the customization category Chassis & Engine in the Customize menu of the Carista app, labeled Disable auto start/stop system and Auto start/stop: remember last state. For more details, visit Carista Audi Compatibility.
Audi MLBevo Cars (A4 B9, A6 C8 and Derivatives)
Disabling the start-stop system on these models requires more creative methods as VAG doesn’t provide an easy way. It involves coding the HVAC (Heater, Ventilation & Air Conditioning) ECU to trick the car into thinking the conditions for normal start-stop operation are not met. This can lead to the start-stop system working again if the air conditioning is turned off. These settings are located in Chassis & Engine, labeled Disable auto start/stop system. For more details, visit Carista Audi Compatibility.
MQB Cars (VW Golf Mk7, Audi A3 Mk3, etc.)
Similar to MLBevo, disabling the start-stop system involves setting minimum voltage and ambient temperature thresholds to unfeasible values. These settings, Disable auto start/stop system (method A) and Disable auto start/stop system (method B), are found in Chassis & Engine. Trying both methods ensures that at least one will disable the system without causing errors.
Considerations
- Warranty and Legal Implications: Disabling the start-stop system might void parts of your vehicle's warranty and could have legal implications depending on local emissions regulations.
- Battery Health: The start-stop system is designed to optimize battery performance, and disabling it may affect battery life.
Additional Information on Start-Stop Systems
Modern start-stop systems have undergone significant engineering to handle the increased number of engine starts and stops. Traditional starting systems were not designed for such frequent use, so components such as the starter motor have been upgraded to handle the demands of the start-stop system. This includes improved gear ratios and enhanced starter motors that reduce wear and tear during frequent use
The start-stop system in Audi and VW vehicles is a sophisticated feature aimed at enhancing fuel efficiency and reducing emissions. While some drivers may prefer to disable it for a more traditional driving experience, it’s essential to understand the potential impacts on vehicle warranty and compliance with local regulations before making any modifications.
Enhanced Features and Functions
- Memory Function: Carista offers a memory function to retain settings, making it easier to manage the start-stop system settings such as: Auto start/stop: remember last state
- Auto Start: The automatic start system ensures that the engine restarts seamlessly when the brake pedal is released or the driver is ready to move again.
- Air Conditioning: The start-stop system takes into account the vehicle's air conditioning needs, restarting the engine if necessary to maintain cabin comfort.