Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
ECO Start/Stop, Basic Function - GF07.10-P-1051A
Engine All (4xWD)
Engine All (CAR)
Overview
This document contains information on:
- General
- Function requirements
- Function
General
For a stationary vehicle, the ECO start/stop function switches the engine off automatically and starts it again, as soon as the driver wishes to drive off. Shutting off the engine when the vehicle is standing still reduces fuel consumption and exhaust gas emissions.
Function requirements
- Ignition ON (circuit 15)
- Engine management ON (circuit 87M)
- Engine in operation
- Outside temperature between -10 and 40°C
- System diagnosis complete and fault-free
- Speed of 8 km/h exceeded previously during forward travel (manual transmission)
- Indicator lamp in the ECO start/stop function button illuminated
Function
All of the systems participating in the ECO start/stop function continuously check their status and transmit this to the powertrain control unit and the combustion engine control unit. After the engine stops, the crankshaft angle in the rest position is stored in the combustion engine control unit using the crankshaft angle sensor. When the engine starts, synchronization of the fuel injection system and the ignition system that is otherwise required is no longer necessary due to the stored crankshaft angle.
Upon activation of the Sport Plus mode, the ECO start/stop function is deactivated.
| Function schematics | |||
| Function schematic for start/stop | Engine 139 in model 118, 177, 247 | PE07.10-P-2509-97A | |
| Additional basic functions | |||
| Automatic start, basic function | GF07.10-P-1052A | ||
| Automatic stop, basic function | GF07.10-P-1053A | ||
| Combustion engine forced start, basic function | GF07.10-P-1059A | ||
| Engine shutoff point detection, basic function | Engine 139, 176, 177, 254, 256, 260, 264, 274, 279, 282 Engine 177, 256 | GF07.10-P-1063B |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.