Your vehicle has what ford calls a smart charging system , it's computer controlled . Battery light on , check charging system message DTC'S diagnostic trouble codes stored , take it to a qualified repair shop - not a parts store .
https://www.youtube.com/watch?v=J4rYSVd588U&t=1s
Principles of Operation
This vehicle is equipped with a powertrain control module (PCM)-controlled charging system whereby the PCM determines the optimal voltage setpoint for the charging system and communicates this information to the voltage regulator. This system is unique in that it has 2 unidirectional communication lines between the PCM and the generator/regulator. Both of these communication lines are pulse-width modulated (PWM). The generator communication (GEN COM) line communicates the desired setpoint from the PCM to the voltage regulator while the generator monitor (GEN MON) line communicates the generator load and error conditions to the PCM. The third pin on the voltage regulator, the A circuit pin, is a dedicated battery voltage sense line.
The charging system voltage is controlled by the PCM. The generator charges the battery, and at the same time supplies power for all of the electrical loads that are required. The battery is more effectively charged with a higher voltage when the battery is cold and a lower voltage when the battery is warm. The PCM is able to adjust the charging voltage according to the battery temperature by using a signal from the intake air temperature (IAT) sensor. This means the voltage setpoint is calculated by the PCM and communicated to the regulator by a communication link.
The PCM simultaneously controls and monitors the output of the generator. When the current consumption is high or the battery is discharged, the system is able to increase the idle speed.
To minimize the engine drag when starting the engine, the PCM controls the generator. The generator does not produce any output until the engine has started. The PCM then progressively increases the output of the generator.
The PCM controls the operation of the charging system warning indicator in the instrument cluster. The PCM is responsible for turning the charging system warning indicator off after the engine is started and illuminating it under fault conditions (when the generator is not generating the correct amount of current with the engine running). The charging system warning indicator is also illuminated by the PCM at key ON engine OFF, and stall condition.
This is a System 4 charging system, which uses the GEN MON and GEN COM lines to control and monitor the charging system through the PCM. System 4 charging systems are virtually identical in design and therefore, share the same diagnostics. The circuit numbers and colors may be different, but the functions are the same. System 4 charging systems may use any type of generator, as the generator type usually depends on the engine packaging and/or output requirements versus cost.
Circuit Description
Positive Battery Output (B+) Terminal Circuit 38 (RD)
Generator output voltage is supplied through the positive battery (B+) output terminal on the rear of the generator to the battery and the electrical system.
Circuit 35 (OG/LB)
This is the A terminal battery voltage sense circuit and is used to sense battery voltage.
Circuit 1816 (YE/LB)
This is the GEN COM circuit. The PCM determines the optimal voltage setpoint for the charging system and communicates the information to the voltage regulator via the GEN COM circuit.
Circuit 1817 (YE)
The GEN MON circuit communicates the generator load and error conditions to the PCM.
Inspection and Verification
WARNING: If equipped with fire suppression system, refer to Section 419-03 for important safety warnings.
WARNING: Batteries contain sulfuric 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. 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.
WARNING: When lifting a battery, excessive pressure on the end walls could cause acid to spew through the vent caps, resulting in personal injury, damage to the vehicle or battery. Lift with a battery carrier or with your hands on opposite corners. Failure to follow these instructions may result in personal injury.
CAUTION: Do not make jumper connections except as directed. Incorrect connections may damage the voltage regulator test terminals, fuses, or fusible links.
CAUTION: Do not allow any metal object to come in contact with the generator housing and internal diode cooling fins. A short circuit may result and burn out the diodes.
NOTE: While carrying out any pinpoint test, disregard the diagnostic trouble codes (DTCs) set while following a specific pinpoint test. After the completion of any test, be sure to clear all DTCs in the PCM.
NOTE: All voltage measurements are referenced to the negative (-) battery post unless otherwise specified.
- Verify the customer concern.
- Visually inspect for obvious signs of mechanical or electrical damage.
Visual Inspection Chart
Mechanical
Electrical
- Battery
- Generator drive belt
- Generator pulley
- Battery junction box (BJB) fuse 6 (15A)
- Fusible link A
- Fusible link B
- Circuitry
- Cables
- Generator
- Powertrain control module (PCM)
- Charging system warning indicator
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
- Verify the battery condition. Refer to Section 414-01 .
- Check the operation of the charging system warning indicator (instrument cluster). Normal operation is as follows:
- With the key OFF, the charging system warning indicator should be off.
- With the key ON and the engine off, the charging system warning indicator should be on.
- With the engine running, the charging system warning indicator should be off.
- Turn off the headlamps and the A/C system (if equipped). Turn the climate control blower to LOW/OFF. Check the battery voltage before and after starting the engine to determine if the battery voltage increases.
- If the cause is not visually evident, connect the diagnostic tool to the data link connector (DLC) and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
- check that the diagnostic card is correctly installed.
- check the connections to the vehicle.
- check the ignition switch position.
- If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.
- Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
- controller area network (CAN), standard corporate protocol (SCP), or International Standards Organization (ISO) circuit fault; all electronic control units no response/not equipped, refer to Section 418-00 .
- No response/not equipped for instrument cluster, refer to Section 413-01 .
- No response/not equipped for PCM, refer to Powertrain Control/Emissions Diagnosis (PC/ED) manual.
- System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out the self-test diagnostics for the PCM.
- If the DTCs retrieved are related to the concern, go to the Powertrain Control Module (PCM) Diagnostic Trouble Code (DTC) Index.
- If no DTCs related to the charging system are retrieved, GO to Symptom Chart .
NOTE: DTC P0622 can be set by the loss of the communication lines between the generator and the PCM. The charging system warning indicator then illuminates until the engine is operated at greater than 4,500 rpm (approximately wide open throttle [WOT]) for a minimum of 3 seconds. At this time, the generator self-excites. The charging system warning indicator remains illuminated, and the generator operates in a default mode (approximately 13.5 volts) until the engine is turned off.