Question edited for clarity.
Question moved to model category.
Jeff's great answer ^^^Up There^^^ is better down here as a Solve.
Jeff Armer Aug 20, 2022
With it running test voltage at the battery. Sounds like it's not charging the battery. Had alternator check? is good, but that doesn't mean it's working in the car. The charging system in your vehicle is computer controlled, is the battery light lit in the instrument cluster ? Could have DTC'S - diagnostic trouble codes stored . Do you know if your car has regulated voltage control or is a none regulated voltage control system.
Charging System Description and Operation (w/RVC)
Electrical Power Management (EPM) Overview
The electrical power management (EPM) system is designed to monitor and control the charging system and send diagnostic messages to alert the driver of possible problems with the battery and generator. This EPM system primarily utilizes existing on-board computer capability to maximize the effectiveness of the generator, to manage the load, improve battery state-of-charge (SOC) and life, and minimize the system's impact on fuel economy. The EPM system performs 3 functions:
• It monitors the battery voltage and estimates the battery condition.
• It takes corrective actions by adjusting the regulated voltage.
• It performs diagnostics and driver notification.
The battery's condition is estimated during key-off and during key-on. During key-off the SOC of the battery is determined by measuring the open-circuit voltage. The SOC is a function of the acid concentration and the internal resistance of the battery, and is estimated by reading the battery open circuit voltage when the battery has been at rest for several hours.
The SOC can be used as a diagnostic tool to tell the customer or the dealer the condition of the battery. Throughout key-on, the algorithm continuously estimates SOC based on adjusted net amp hours, battery capacity, initial SOC, and temperature.
While running, the battery's degree of discharge is primarily determined by a battery current sensor, which is integrated to obtain net amp hours.
In addition, the EPM function is designed to perform regulated voltage control (RVC) to improve battery SOC, battery life, and fuel economy. This is accomplished by using knowledge of the battery's SOC and temperature to set the charging voltage to an optimum battery voltage level for recharging without detriment to battery life.
The Charging System Description and Operation is divided into 3 sections. The first section describes the charging system components and their integration into the electrical power management (EPM). The second section describes charging system operation. The third section describes the instrument panel cluster (IPC) operation of the charge indicator, driver information center (DIC) messages, and voltmeter operation.
Charging System Description and Operation (w/o RVC)
Circuit Description
The generator provides voltage to operate the vehicle's electrical system and to charge its battery. A magnetic field is created when current flows through the rotor. This field rotates as the rotor is driven by the engine, creating an AC voltage in the stator windings. The AC voltage is converted to DC by the rectifier bridge and is supplied to the electrical system at the battery terminal.
When the engine is running, the generator turn (on) signal is sent to the generator from the powertrain control module (PCM), turning ON the regulator. The generator's voltage regulator controls current to the rotor, thereby controlling the output voltage. The rotor current is proportional to the electrical pulse width supplied by the regulator. When the engine is started, the regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once the engine is running, the regulator varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation. The generator F-terminal is connected internally to the voltage regulator and externally to the PCM. When the voltage regulator detects a charging system problem, it grounds this circuit to signal the PCM that a problem exists. The PCM monitors the generator field duty cycle signal circuit.
Charging System Indicator
The instrument panel cluster (IPC) illuminates the charge indicator in the message center when the following occurs:
• The powertrain control module (PCM) detects that the generator output is less than 11 volts or greater than 16 volts. The IPC receives a serial data message from the PCM requesting illumination.
• The IPC determines that the system voltage is less than 11 volts or greater than 16 volts. The IPC receives a serial data message from the body control module (BCM) indicating the system voltage.
• The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.
• The ignition is ON, with the engine OFF.
Did you test for battery voltage on larger wire on the back of the alternator - could have a bad wire -corrosion inside you can't see . Could also have blown fusible link on that wire - comes from the starter B+ post.
Does it have a Battery Current Sensor on the negative battery cable - battery negative post ?
https://www.youtube.com/watch?v=FI4Jn4Ho...
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