Engine Electrical System
Repair Procedures
In this manual: Engine Electrical System
25steps
~150min
5/5difficulty
Done 0 of 25
Inspection
Inspection Item
- Battery Performance Check
- Battery Voltage Check
- Charging Voltage Check
- General Inspection
- Terminal Tightness Check
- Engine / Transmission Condition Check
- Wiring Harness Ground Condition Check
- Specified Electrical Value Check
- Vehicle Parasitic Current Check
- Battery Capacity Check
- After driving the vehicle, if 20 minutes have not passed since the engine was stopped, turn the ignition key ON and turn on the electrical systems (headlights, blower motor, rear window defroster, etc.) for 60 seconds to remove the surface charge.
- Turn the ignition OFF and turn off the electrical systems.
- Measure the battery voltage between the battery negative (-) and positive (+) terminals.
Standard voltage: Approximately 12.5 - 12.9 V [20 °C]
If the voltage is below the specified value, charge the battery. - Make sure the battery terminals are not loose or corroded. (See Charging System - Battery)
- Check the fuses for continuity.

- Measure the voltage as shown in the illustration below.
Standard value: Approximately 0 V

- If the generator fuse is blown, replace it in accordance with the procedure below:
a. Turn the ignition switch OFF and disconnect the battery negative (-) terminal. b. Remove the generator fuse after loosening the nuts (A). b. Replace the regular alternator fuse or the battery cable. 
d. Install in the reverse order of removal.
- Check the battery sensor fuse (A) for continuity.

- Replace with a standard battery sensor fuse.
- Measure the voltage.
Standard value: Approximately 0 V
- Measure the voltage as shown in the illustration below.
- Inspect the drive belt
- Visually inspect the belt for excessive wear, frayed cords, etc. If any defect is found, replace the drive belt.

- Visually inspect the belt for excessive wear, frayed cords, etc. If any defect is found, replace the drive belt.
- Measure and adjust the drive belt tension. (Refer to Engine Mechanical System - "Drive Belt")
- Visually inspect the alternator wiring and listen for abnormal noise.
- Make sure the wiring is in good condition.
- Make sure there is no abnormal noise from the generator while the engine is running.
- Check the charge warning lamp circuit.
- Warm up the engine, then turn it off.
- Turn off all accessories.
- Turn the ignition switch ON. Make sure the charge warning light illuminates.
- Start the engine. Make sure the light goes off. If the light does not go off as specified, troubleshoot the charge warning light circuit.
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 CheckInspection of Wiring Harness Condition

| 1. Engine ground (Engine ↔ Chassis) 2. Transmission ground (Transmission ↔ Chassis) |
Specified Electrical Value Check (Using Voltmeter and Ammeter)
- Generator Output Wire Voltage Drop Test. This test determines whether the wiring between generator terminal "B" and the battery terminal (+) is in good condition using the voltage drop method.
- Preparation
a. Turn the ignition switch to the OFF position. b. Disconnect the output wire from generator terminal "B". Connect the ammeter (+) lead to generator terminal "B" and the ammeter (-) lead to the output wire. Connect the voltmeter (+) lead to generator terminal "B" and the voltmeter (-) lead to the battery (+) terminal. 
- Test
a. Start the engine. b. Turn on the headlights and blower motor, adjust the engine speed until the ammeter shows 20 A, and read the voltmeter. - Result
a. The voltmeter may show the standard value. Standard value: 0.2 V max.
b. If the voltmeter reading is higher than expected (more than 0.2 V maximum), a wiring fault is suspected. In this case, inspect the wiring from generator terminal "B" to the battery (+) terminal. Check for loose connections, discoloration due to harness overheating, etc. Repair them before retesting. b. After the inspection is completed, set the engine speed to idle. Turn off the headlights, blower motor and ignition switch.
- Preparation
- Output Current Test. This test determines whether the generator produces output current equivalent to normal output.
- 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 the "Battery" section for battery inspection. The battery used for the output current test should be partially discharged. If the battery is fully charged, the test may not be performed correctly due to insufficient load. Check the generator drive belt tension. Refer to the "Drive Belt Inspection" section for belt tension inspection. b. Turn the ignition off. b. Disconnect the battery ground cable. d. Disconnect the generator output wire from generator terminal "B". e. Connect a DC ammeter (0 to 150 A) in series between generator terminal "B" and the disconnected output wire. Be sure to connect the ammeter (-) lead to the disconnected output wire. f. Connect a voltmeter (0 to 20 V) between generator terminal "B" and ground. Connect the voltmeter (+) lead to generator terminal "B" and the (-) lead to ground. g. Connect the battery ground cable. h. Leave the engine hood open. 


- Test
a. Make sure the voltmeter shows the same value as the battery voltage. If the voltmeter shows 0 V, there is an open circuit in the wire between generator terminal "B" and the battery (+) terminal, or a poor ground connection. b. Start the engine and turn on the headlights. b. Set the headlights to high beam and the blower fan switch to HIGH, quickly increase the engine speed to 2500 rpm, and read the maximum output current shown on the ammeter. - Result
a. The ammeter reading should be above the specified limit value. If it is below, even though the generator output wire is in good condition, remove the generator from the vehicle and test it. Limit value: 60% of the current rating
b. After completing the output current test, 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.
- Preparation
- Regulated Voltage Test. The purpose of this test is to check that the electronic voltage regulator correctly regulates the voltage.
- 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 the "Battery" section to check the battery. Check the generator drive belt tension. Refer to the "Inspect Drive Belt" section to check belt tension. b. Turn the ignition switch to the OFF position. b. Disconnect the negative (-) battery terminal. d. Connect a digital voltmeter between the generator B terminal and ground. Connect the (+) voltmeter lead to the generator B terminal. Connect the (-) lead to a good ground or the battery (-) terminal. e. Disconnect the generator output wire from generator terminal "B". f. Connect a DC ammeter (0 to 150 A) in series between the B terminal and the disconnected output wire. Connect the (-) ammeter lead to the disconnected output wire. g. Connect the negative (-) battery terminal. 


- Test
a. Turn the ignition switch ON and check that the voltmeter shows the following value. Voltage: Battery voltage
If it indicates 0 V, there is an open circuit in the wire between the generator B terminal and the battery, or 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. - Result
a. If the voltmeter reading does not meet the standard 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 standard 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.
- Preparation
- Generator Output Wire Voltage Drop Test. This test determines whether the wiring between generator terminal "B" and the battery terminal (+) is in good condition using the voltage drop method.
- Preparation
a. Turn the ignition switch to the OFF position. b. Install a clamp-type ammeter around the positive (+) wire between the battery and the generator B terminal. b. Connect the (+) voltmeter lead to the generator B terminal and the (-) voltmeter lead to the battery (+) terminal. 
- Test
a. Start the engine. b. Turn on the headlights and blower motor, adjust the engine speed until the ammeter shows 20 A, and read the voltmeter. - Result
a. The voltmeter may show the standard value. Standard value: 0.2 V max.
b. If the voltmeter reading is higher than expected (more than 0.2 V maximum), a wiring fault is suspected. In this case, inspect the wiring from generator terminal "B" to the battery (+) terminal. Check for loose connections, discoloration due to harness overheating, etc. Repair them before retesting. b. After the inspection is completed, set the engine speed to idle. Turn off the headlights, blower motor and ignition switch.
- Preparation
- Output Current Test. This test determines whether the generator produces output current equivalent to normal output.
- 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 the "Battery" section to check the battery. The battery used for the output current test should be partially discharged. If the battery is fully charged, the test may not be performed correctly due to insufficient load. Check the generator drive belt tension. Refer to the "Inspect Drive Belt" section to check belt tension. b. Turn the ignition off. b. Disconnect the negative (-) battery terminal. d. Install a clamp-type ammeter around the positive (+) wire between the battery and the generator B terminal. e. Connect a DC ammeter (0 to 150 A) in series between generator terminal "B" and the disconnected output wire. Be sure to connect the ammeter (-) lead to the disconnected output wire. f. Connect a voltmeter (0 to 20 V) between generator terminal "B" and ground. Connect the voltmeter (+) lead to generator terminal "B" and the (-) lead to ground. g. Connect the negative (-) battery terminal. h. Leave the engine hood open. 


- Test
a. Make sure the voltmeter shows the same value as the battery voltage. If the voltmeter shows 0 V, there is an open circuit in the wire between generator terminal "B" and the battery (+) terminal, or a poor ground connection. b. Start the engine and turn on the headlights. b. Set the headlights to high beam and the blower fan switch to HIGH, quickly increase the engine speed to 2500 rpm, and read the maximum output current shown on the ammeter. - Result
a. The ammeter reading should be above the specified limit value. If it is below, even though the generator output wire is in good condition, remove the generator from the vehicle and test it. Limit value: 60% of the current rating
b. After completing the output current test, 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.
- Preparation
- Regulated Voltage Test. The purpose of this test is to check that the electronic voltage regulator correctly regulates the voltage.
- 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 the "Battery" section to check the battery. Check the generator drive belt tension. Refer to the "Inspect Drive Belt" section to check belt tension. b. Turn the ignition switch to the OFF position. b. Disconnect the negative (-) battery terminal. d. Connect a digital voltmeter between the generator B terminal and ground. Connect the (+) voltmeter lead to the generator B terminal. Connect the (-) lead to a good ground or the battery (-) terminal. e. Disconnect the generator output wire from generator terminal "B". f. Connect a DC ammeter (0 to 150 A) in series between the B terminal and the disconnected output wire. Connect the (-) ammeter lead to the disconnected output wire. g. Connect the negative (-) battery terminal. 


- Test
a. Turn the ignition switch ON and check that the voltmeter shows the following value. Voltage: Battery voltage
If it indicates 0 V, there is an open circuit in the wire between the generator B terminal and the battery, or 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. - Result
a. If the voltmeter reading does not meet the standard 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 standard 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.
- Preparation
- Turn off all electrical devices, then turn the ignition OFF.
- Close all doors except the hood, then lock all doors.
- Disconnect the hood switch connector.
- Close the liftgate.
- Close the doors or remove the door switches.
- Wait several minutes until the vehicle electrical systems enter sleep mode.
- Connect the ammeter in series between the negative (-) battery terminal and the ground cable, then slowly disconnect the clamp from the negative (-) battery terminal.

- Read the ammeter current value.
- If the parasitic current exceeds the limit value, search for the abnormal circuit by removing the fuses one at a time and checking the parasitic current.
- Connect only the fuse suspected of parasitic current and search for the faulty unit by disconnecting the components connected to the circuit one at a time until the parasitic draw drops below the limit value.
Limit value (after 10-20 min.): Less than 50 mA
- Turn off all electrical devices, then turn the ignition OFF.
- Close all doors except the hood, then lock all doors.
- Disconnect the hood switch connector.
- Close the liftgate.
- Close the doors or remove the door switches.
- Wait several minutes until the vehicle electrical systems enter sleep mode.
- Install the clamp-type ammeter on the negative (-) battery terminal.

- Read the ammeter current value.
- If the parasitic current exceeds the limit value, search for the abnormal circuit by removing the fuses one at a time and checking the parasitic current.
- Connect only the fuse suspected of parasitic current and search for the faulty unit by disconnecting the components connected to the circuit one at a time until the parasitic draw drops below the limit value.
Limit value (after 10-20 min.): Less than 50 mA
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