PRE-RELEASE
Brief description
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Engine Control Module (ECM)
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MIU (540)/SID (541)
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Generator (2)
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Battery (1)
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Column Integration Module, CIM (703a)
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| Description |
Battery
The terminal voltage of the battery is 12V and its capacity is dependent on the engine variant. The battery delivers current to the starter motor for starting the engine and supplies other power consumers with current while the engine is not running. The positive battery terminal is connected to the starter motor and to the main fuse box in the engine bay and its negative terminal is connected to the body and the engine.The battery is located on the left-hand side of the engine bay. On some variance, it is contained in a battery cover to reduce heating. An air duct takes in air via the car's grille. The air from the air duct passes through the battery cover and consequently cools down the battery.
The battery electrolyte cannot be topped up. The battery electrolyte level is indicated by an indicator point on the top of the battery. If the indicator is dark, the level is OK. On low level the indicator is light and the battery should be changed.
Alternator
The task of the generator is to supply power to all consumers when the engine has started, and to charge the battery. The generator is an AC generator with integral charge control.The generator is driven by the engine via a poly-V belt from the crankshaft pulley. The engine control module determines when the generator should begin charging, which takes place when the control module receives a signal that the engine has started. If a charging fault occurs, the generator sends information on this to the engine control module. The engine control module sends the information, via the CIM to the MIU/SID which indicates that charging is not working. A diagnostic trouble code is generated in the engine control module.
Warning indicator for charging
The charge warning indicator advises the driver whether or not the generator is charging. If the generator is not charging then a symbol is shown as well as a warning text in the SID. When no warning message is shown, the generator is charging. Information on the generator's charging status is sent via a cable to the engine control module. The MIU receives information via a bus message from the engine control module as to whether or not the generator is charging. A warning indicator is shown in the SID. When the ignition is on and the engine is not running there is no warning message shown in the SID.
Battery current sensor
The battery current sensor (343) together with BCM (707) is used to optimise the battery charging to ensure reduced fuel consumption, a high charge level and long battery life. By taking into account the current at the battery negative terminal, the battery voltage and temperature, the optimum charging current can be calculated which forms the basis for how the alternator charge should be controlled. The battery voltage is measured partly when the battery has been at rest for several hours, and partly when it is in use.
