Vehicle electricsStart/stop system
| The start/stop system is used for reducing fuel consumption by automatically switching off the engine when the vehicle is stationary and automatically starting it when the driver wants the vehicle to move on. The start/stop mode is automatically activated when, after starting to move, the vehicle is driven for about 4 seconds at a minimum speed of 3 km/h. |
| Following control units are involved in the start/stop system: |
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| Data bus diagnostic interface -J533- in the onboard power supply control unit -J519- |
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| Engine control unit -J623- |
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| ABS control unit -J104- |
| Battery recharging or jump start on vehicles with start/stop system: |
| When recharging or jump starting vehicles with start/stop system, note the following: first connect charging cable to battery positive terminal, then body earth. This ensures that the battery sensor is not bridged. The direct charging of the battery on the negative terminal clamp means that the battery sensor is shunted and the battery data are not registered by the sensor while charging. Then, the values concerning the battery state and saved in the data bus diagnostic interface would not correspond to the values of the charged battery. |
| Replacing battery on vehicles with start/stop system: |
| Because of its higher deep-cycle resistance, only a special starter battery is used in vehicles with a start/stop system. |
| When renewing the starter battery, note correct part designation in → ETKA (electronic parts catalogue). Starter batteries for use in vehicles with a start/stop system are marked with „AGM“ (Absorbent Glass Mat) or „EFB“ (Enhanced Flooded Battery). |
| Fault detection and fault display: |
| The start/stop system as a function is integrated in the engine control unit -J623- software. |
| The engine control unit -J623- features self-diagnosis to facilitate fault finding. |
| To localise faults, refer to chapter entitled „Vehicle diagnosis, testing and information system“ and use „Guided fault finding“ function. |
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03 General
