Refer to Wiring Diagrams Section 414-02, for schematic and connector information.
Ford approved diagnostic tool
Surface charge dissipation unit (SCD²)
Micro390 battery tester
Principles of Operation
The charging system for this vehicle is composed of a generator combined with a generator control module.
The generators for some variants are equipped with pulleys with built in reverse rotation clutches. These pulleys allow the generator armature to free-wheel during sudden engine deceleration so smoothing the reduction in charge rate output. This also reduces the load changes on the accessory drive belt.
Charging Control
2
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Generator control module
3
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Local interconnect network (LIN) communication
4
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Powertrain control module (PCM)
5
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Control area network (CAN) communication
6
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General electronic module (GEM)
Charging is controlled by the PCM and the GEM. The PCM communicates with the generator control module using a LIN connection. The PCM will instruct the generator to increase or decrease charging voltages in accordance with the requirements of the power supply systems. In turn the generator control module will inform the PCM of the current output of the generator.
The generator control module monitors the generator output. If a fault develops in the generator control module, control circuits or the generator, the PCM will be informed and a diagnostic trouble code (DTC) will be set.
Using the information received by the PCM from the generator control module, the PCM can calculate the generator load. The generator load information is transferred to the GEM using CAN communication. The GEM uses the load information to calculate maximum allowable current consumption of the climate related systems. The GEM also controls the initiation of fault warnings to the display information module. The battery charge warning indicator is turned off by means of an instruction from the GEM using CAN communication.
To reduce the load on the generator to within its working limits and assist with battery recovery after start up, the GEM will switch non critical systems off and on.
The systems that are controlled by the GEM have typical loads of:
- Heated windshield
- Heated rear screen
- Heated mirrors
- Supplementary heating
The climate systems have been chosen because they can be switched off for short periods of time with barely detectable changes in their ultimate function. During this control period, the function indicators for the system being controlled will remain illuminated. The total load reduction if all controlled components where switched off would be in the region of 180 amps.
Conversely, the GEM can switch the same components on at any time thereby increasing engine load. This function is used to assist with the engine warm up process.
Inspection and Verification
WARNING:Batteries contain sulphuric acid. Avoid contact with skin, eyes, or clothing. Also, shield your eyes when working near batteries to protect against possible splashing of the acid solution. In case of acid contact with skin or eyes, flush immediately with water for a minimum of 15 minutes and get prompt medical attention. If acid is swallowed, call a physician immediately. Failure to follow these instructions may result in personal injury.
WARNING:Batteries normally produce explosive gases which can cause personal injury. Therefore, do not allow flames, sparks or lighted substances to come near the battery. When charging or working near a battery, always shield your face and protect your eyes. Always provide ventilation. Failure to follow these instructions may result in personal injury.
- Verify the customer concern.
- Visually inspect for obvious signs of mechanical or electrical damage.
Visual Inspection Chart
*In addition, it is advisable to check the vehicle electrical system. Check that the generator is functioning correctly and that all key-off loads (luggage compartment lamps, glove compartment lamp and interior lamps) are not staying on.
