Charging System

Components and Component Location

Components

① ECM ② Battery ③ Alternator ④ Starter ⑤ Instrument cluster ⑥ Ignition switch or Start/Stop button ⑦ Battery sensor ⑧ Hood switch

Description and Operation

Description

The charging system consists of the battery, the alternator with built-in regulator, the charge warning light and the wiring. The alternator has eight built-in diodes, each of which converts alternating current to direct current. Therefore, direct current appears at the alternator B terminal. The charging voltage of this alternator is regulated by the battery voltage sensing system. The main components of the alternator are the rotor, stator, rectifier, capacitor, brushes, bearings and V-ribbed belt pulley. The brush holder contains a built-in electronic voltage regulator. Generator Control System: The generator control system controls the charging voltage setpoint to improve fuel economy, manages generator load under various operating conditions, keeps the battery charged and protects the battery from overcharging. The ECM controls the generating voltage by duty cycle (charge control, discharge control, normal control) depending on battery conditions and vehicle operating conditions. The system performs discharge control when the vehicle accelerates. The vehicle reduces generator load and draws electrical power from the battery. The system performs charge control when the vehicle decelerates. The vehicle increases generator load and charges the battery.

Circuit Diagrams

Wiring Diagram

Repair Procedures

Inspection

Inspection Item

• Battery Performance Check
• Battery Voltage Check
• Charging Voltage Check
• General Inspection
• Terminal Tightness Check
• Engine/Transaxle Condition Check
• Wiring Harness Ground Condition Check
• Electrical Characteristics Inspection
• Vehicle Parasitic Current Check
• Battery Capacity Check

Battery Performance CheckBattery Voltage Check

1. 1
   After driving the vehicle, if 20 minutes have not elapsed since the engine was stopped, turn the ignition ON and operate electrical loads (headlamps, blower motor, rear window defroster, etc.) for 60 seconds to remove the surface charge.
2. 2
   Turn the ignition OFF and turn off the electrical systems.
3. 3
   Measure the battery voltage between the negative (-) and positive (+) battery terminals.

   Standard voltage: Approximately 12.5-12.9 V [at 20 °C]

   If the voltage is below the specified value, charge the battery.
4. 4
   Make sure the battery terminals are not loose or corroded. (See Charging System - Battery)
5. 5
   Check the fuse for continuity. Alternator fuse

   1. Check the alternator fuse for continuity.

      

   2. Measure the voltage as shown in the illustration below.

      Standard value: Approximately 0 V

      

   3. If the generator fuse is blown, replace it as follows:

      a.	Turn the ignition switch OFF and disconnect the negative (-) battery terminal.

      b.	Remove the battery positive (+) cable nut.

      b.	Replace the generator fuse or battery cable with the original part.

      d.	Install in the reverse order of removal.

6. 6
   Inspect the drive belt.

   1. Visually inspect the belt for excessive wear, frayed cords, etc. If any defect is found, replace the drive belt.

      

7. 7
   Measure and adjust the drive belt tension. (Refer to Engine Mechanical System - "Drive Belt")
8. 8
   Visually inspect the alternator wiring and listen for abnormal noise.

   1. Make sure the wiring is in good condition.
   2. Make sure there is no abnormal noise from the alternator with the engine running.
9. 9
   Inspect the charge warning light circuit.

   1. Warm up the engine, then turn it off.
   2. Turn off all accessories.
   3. Turn the ignition switch ON. Check that the charge warning light illuminates.
   4. Start the engine. Check that the light goes off. If the light does not go off as specified, troubleshoot the charge warning light circuit.

General Inspection, Terminal Clamping State

Location of check component

1. Alternator B+ terminal 2. Engine compartment fuse and relay block positive (+) terminal 3. Battery positive (+) terminal

4. Battery negative (-) terminal 5. Body ground

Engine / Transmission Condition CheckWiring Harness Ground Condition Check

1. Engine ground (engine to body) 2. Transaxle ground (transaxle to body)

Specified Electrical Value Check (Using Voltmeter and Ammeter)

1. 1
   Alternator Output Wire Voltage Drop Test
   This test checks whether the wiring between the alternator "B" terminal and the battery (+) terminal is in good condition by the voltage drop method.

   1. Preparation

      a.	Turn the ignition switch to the OFF position.

      b.

      Disconnect the output wire from the alternator "B" terminal. Connect the (+) lead of the ammeter to the alternator "B" terminal, and connect the (-) lead of the ammeter to the output wire. Connect the (+) lead of the voltmeter to the alternator "B" terminal, and connect the (-) lead of the voltmeter to the battery (+) terminal.

   2. Test

      a.	Start the engine.

      b.	Turn on the headlamps and blower motor. Adjust the engine speed until the ammeter shows 20 A, then read the voltmeter.

   3. Result

      a.	The voltmeter should show the value specified. Standard value: 0.2 V max.

      b.

      If the voltmeter reading is higher than specified (more than 0.2 V maximum), the wiring may be faulty. In this case, inspect the wiring from the alternator "B" terminal to the battery (+) terminal. Check for loose connections, discoloration due to harness overheating, etc. Repair them before retesting.

      b.	After the test is completed, return engine speed to idle. Turn off the headlights, blower motor and ignition switch.

2. 2
   Alternator Output Current Test. This test determines whether the alternator produces output current equivalent to normal output current.

   1. Preparation

      a.

      Before testing, check the following items and correct as necessary. Check the battery installed in the vehicle to make sure it is in good condition. Refer to Battery for battery inspection. The battery used for the output current test must be partially discharged. If the battery is fully charged, the test may not be performed correctly due to insufficient load. Check the alternator drive belt tension. Refer to Drive Belt Inspection for belt tension inspection.

      b.	Turn the ignition off.

      b.	Disconnect the battery ground cable.

      d.	Disconnect the alternator output wire from the alternator "B" terminal.

      e.	Connect a DC ammeter (0 to 150 A) in series between the "B" terminal and the disconnected output wire. Be sure to connect the (-) lead of the ammeter to the disconnected output wire.

      f.	Connect a voltmeter (0 to 20 V) between the "B" terminal and ground. Connect the (+) lead to the alternator "B" terminal and the (-) lead to a good ground.

      g.	Connect the battery ground cable.

      h.	Leave the engine hood open.

   2. Test

      a.	Check that the voltmeter reading is equal to the battery voltage. If the voltmeter reads 0 V, there is an open circuit in the wire between the alternator "B" terminal and the battery (+) terminal, or a poor ground.

      b.	Start the engine and turn on the headlights.

      b.	Turn the headlamps to high beam and set the blower motor to HIGH. Then quickly increase the engine speed to 2500 rpm and read the maximum output current indicated on the ammeter.

   3. Result

      a.	The ammeter reading must be above the specified limit. If it is below the limit even though the alternator output wire is in good condition, remove the alternator from the vehicle and inspect it. Limit value: 60% of the voltage standard

      b.	After completing the output current check, reduce the engine speed to idle and turn the ignition switch OFF.

      b.	Disconnect the negative (-) battery terminal.

      d.	Remove the ammeter, voltmeter and engine tachometer.

      e.	Connect the generator output wire to the generator "B" terminal.

      f.	Connect the negative (-) battery terminal.

3. 3
   Regulated Voltage Test. The purpose of this test is to check that the electronic voltage regulator controls the voltage correctly.

   1. Preparation

      a.	Before testing, check the following items and correct as necessary. Make sure the battery installed in the vehicle is fully charged. Refer to Battery for battery inspection. Check the alternator drive belt tension. Refer to Drive Belt Inspection for belt tension inspection.

      b.	Turn the ignition switch to the OFF position.

      b.	Disconnect the negative (-) battery terminal.

      d.	Connect a digital voltmeter between the alternator "B" terminal and ground. Connect the (+) lead of the voltmeter to the alternator "B" terminal. Connect the (-) lead to a good ground or the battery (-) terminal.

      e.	Disconnect the alternator output wire from the alternator "B" terminal.

      f.	Connect a DC ammeter (0 to 150 A) in series between the "B" terminal and the disconnected output wire. Connect the (-) lead of the ammeter to the disconnected output wire.

      g.	Connect the negative (-) battery terminal.

   2. Test

      a.	Turn the ignition switch ON and check that the voltmeter shows the following value. Voltage: Battery voltage If the voltmeter reads 0 V, there is an open circuit in the wire between the alternator "B" terminal, the battery, and the battery (-) terminal.

      b.	Start the engine. Turn off all lights and accessories.

      b.	Run the engine at approximately 2500 rpm and read the voltmeter when the generator output current drops to 10 A or less.

   3. Result

      a.	If the voltmeter reading does not meet the specified value, the voltage regulator or the generator is faulty. Regulated voltage: 11.7–15.3 V

      b.	If the voltmeter reading does not meet the specified value, the voltage regulator or the generator is faulty.

      b.	Disconnect the negative (-) battery terminal.

      d.	Remove the voltmeter and ammeter.

      e.	Connect the generator output wire to the generator "B" terminal.

      f.	Connect the negative (-) battery terminal.

4. 4
   Alternator Output Wire Voltage Drop Test
   This test checks whether the wiring between the alternator "B" terminal and the battery (+) terminal is in good condition by the voltage drop method.

   1. Preparation

      a.	Turn the ignition switch to the OFF position.

      b.	Install a clamp-type ammeter between the positive (+) battery terminal and the generator "B" terminal.

      b.	Connect the (+) lead of the voltmeter to the alternator "B" terminal and the (-) lead of the voltmeter to the battery (+) terminal.

      

   2. Test

      a.	Start the engine.

      b.	Turn on the headlamps and blower motor. Then adjust the engine speed until the ammeter shows 20 A, and read the voltmeter.

   3. Result

      a.	The voltmeter should show the value specified. Standard value: 0.2 V max.

      b.	If the voltmeter reading is higher than specified (up to 0.2 V), the wiring may be faulty. In this case, inspect the wiring from the alternator "B" terminal to the battery (+) terminal. Check for loose connections, discoloration due to harness overheating, etc. Repair them before retesting.

      b.	After the test is complete, set the engine speed to idle. Turn off the headlights, cooling fan and ignition switch.

5. 5
   Alternator Output Current Test. This test determines whether the alternator produces output current equivalent to normal output current.

   1. Preparation

      a.

      Before testing, check the following items and correct as necessary. Check the battery installed in the vehicle to make sure it is in good condition. Refer to Battery for battery inspection. The battery used for the output current test must be partially discharged. If the battery is fully charged, the test may not be performed correctly due to insufficient load. Check the alternator drive belt tension. Refer to Drive Belt Inspection for belt tension inspection.

      b.	Turn the ignition off.

      b.	Disconnect the negative (-) battery terminal.

      d.	Install a clamp-type ammeter between the positive (+) battery terminal and the generator "B" terminal.

      e.	Connect a DC ammeter (0 to 150 A) in series between the "B" terminal and the disconnected output wire. Be sure to connect the (-) lead of the ammeter to the disconnected output wire.

      f.	Connect a voltmeter (0 to 20 V) between the "B" terminal and ground. Connect the (+) lead to the alternator "B" terminal and the (-) lead to a good ground.

      g.	Connect the negative (-) battery terminal.

      h.	Leave the engine hood open.

   2. Test

      a.	Check that the voltmeter reading is equal to the battery voltage. If the voltmeter reads 0 V, there is an open circuit in the wire between the alternator "B" terminal and the battery (+) terminal, or a poor ground.

      b.	Start the engine and turn on the headlights.

      b.	Turn the headlamps to high beam and set the blower motor to HIGH. Then quickly increase the engine speed to 2500 rpm and read the maximum output current on the ammeter.

   3. Result

      a.	The ammeter reading must be above the specified limit. If it is below the limit even though the alternator output wire is in good condition, remove the alternator from the vehicle and inspect it. Limit value: 60% of the voltage standard

      b.	After completing the output current check, reduce the engine speed to idle and turn the ignition switch OFF.

      b.	Disconnect the negative (-) battery terminal.

      d.	Remove the ammeter, voltmeter and engine tachometer.

      e.	Connect the generator output wire to the generator "B" terminal.

      f.	Connect the negative (-) battery terminal.

6. 6
   Regulated Voltage Test. The purpose of this test is to check that the electronic voltage regulator controls the voltage correctly.

   1. Preparation

      a.	Before testing, check the following items and correct as necessary. Make sure the battery installed in the vehicle is fully charged. Refer to Battery for battery inspection. Check the alternator drive belt tension. Refer to Drive Belt Inspection for belt tension inspection.

      b.	Turn the ignition switch to the OFF position.

      b.	Disconnect the negative (-) battery terminal.

      d.	Connect a digital voltmeter between the alternator "B" terminal and ground. Connect the (+) lead of the voltmeter to the alternator "B" terminal. Connect the (-) lead to a good ground or the battery (-) terminal.

      e.	Disconnect the alternator output wire from the alternator "B" terminal.

      f.	Connect a DC ammeter (0 to 150 A) in series between the "B" terminal and the disconnected output wire. Connect the (-) lead of the ammeter to the disconnected output wire.

      g.	Connect the negative (-) battery terminal.

   2. Test

      a.	Turn the ignition switch ON and check that the voltmeter shows the following value. Voltage: Battery voltage If the voltmeter reads 0 V, there is an open circuit in the wire between the alternator "B" terminal, the battery, and the battery (-) terminal.

      b.	Start the engine. Keep all lights and accessories turned off.

      b.	Run the engine at approximately 2500 rpm and read the voltmeter when the generator output current drops to 10 A or less.

   3. Result

      a.	If the voltmeter reading does not meet the specified value, the voltage regulator or the generator is faulty. Regulated voltage: 11.7–15.3 V

      b.	If the voltmeter reading does not meet the specified value, the voltage regulator or the generator is faulty.

      b.	Disconnect the negative (-) battery terminal.

      d.	Remove the voltmeter and ammeter.

      e.	Connect the generator output wire to the generator "B" terminal.

      f.	Connect the negative (-) battery terminal.

7. 7
   Turn off all electrical devices, then turn the ignition off.
8. 8
   Close all doors except the hood, then lock all doors.

   1. Disconnect the hood switch connector.
   2. Close the liftgate.
   3. Close the doors or remove the door switches.
9. 9
   Wait several minutes until the vehicle electrical systems go into sleep mode.
10. 10
    Connect an ammeter in series between the battery (-) terminal and the ground cable, then disconnect the clamp from the battery (-) terminal slowly.

    

11. 11
    Read the ammeter current value.

    • If the parasitic current exceeds the specified limit, search for the abnormal circuit by removing the fuses one by one and checking the parasitic current.
    • Reconnect only the fuse suspected of parasitic current, and locate the faulty unit by disconnecting the components connected to the circuit one at a time until the parasitic draw drops below the specified limit.

    Limit value (after 10–20 min.): below 50 mA.

12. 12
    Turn off all electrical devices, then turn the ignition off.
13. 13
    Close all doors except the hood, then lock all doors.

    1. Disconnect the hood switch connector.
    2. Close the liftgate.
    3. Close the doors or remove the door switches.
14. 14
    Wait several minutes until the vehicle electrical systems go into sleep mode.
15. 15
    Install the clamp-type ammeter on the negative (-) battery terminal.

    

16. 16
    Read the ammeter current value.

    • If the parasitic current exceeds the specified limit, search for the abnormal circuit by removing the fuses one by one and checking the parasitic current.
    • Reconnect only the fuse suspected of parasitic current, and locate the faulty unit by disconnecting the components connected to the circuit one at a time until the parasitic draw drops below the specified limit.

    Limit value (after 10–20 min.): below 50 mA.

Electrical Characteristics Inspection (Using Voltmeter and Clamp-Type Ammeter) Vehicle Parasitic Current Check [Using Ammeter] [Using Clamp-Type Ammeter]

Troubleshooting

Troubleshooting

Symptom	Suspect area	Remedy
The charge warning light does not come on when the ignition switch is in the "ON" position and the engine is off.	Blown fuse	Check fuses
	Bulb burnt out	Replace bulb
	Loose wiring connection	Tighten loose connection
	Electronic voltage regulator	If the light goes off, replace the voltage regulator.
The charge warning light does not go off with the engine running. (Battery requires frequent recharging)	Drive belt loose or worn	Adjust belt tension or replace belt
	Battery cable loose, corroded or worn	Inspect cable connection, repair or replace cable
	Electronic voltage regulator or alternator	If indicator goes off, replace voltage regulator or alternator.
	Wiring	Repair or replace wiring
Overcharging	Electronic voltage regulator	If indicator goes off, replace voltage regulator.
	Voltage sensor wire	Repair or replace wiring
Dismiss	Drive belt loose or worn	Adjust belt tension or replace belt
	Wiring connection loose or short circuit	Check wiring connection, repair or replace wiring
	Electronic voltage regulator or alternator	If indicator goes off, replace voltage regulator or alternator.
	Poor ground	Inspect or repair the ground connection.
	Worn battery	Replace battery