Alternator: Testing and Inspection
GENERATOR INSPECTIONGenerator Warning Light
1. Verify that the battery is fully charged.
- Charge if necessary.
2. Turn the ignition switch on and verify that the generator warning light illuminates.
- If not as specified, inspect generator warning light, wiring harnesses between the battery and the generator warning light.
3. Verify that the generator warning light goes out after the engine is started.
- If not as specified, inspect if any of the following DTCs are displayed: P0112, P0113, P2502, P2503, P2504. (See ON-BOARD DIAGNOSTIC TEST [L3].) (See ON-BOARD DIAGNOSTIC TEST [AJ].)
Generator
Voltage
1. Verify that the battery is fully charged.
- Charge if necessary.
2. Turn off all electrical loads.
3. Turn the ignition switch to start the engine and verify while the engine is running.
4. Measure the voltage at the terminals shown in the table.
- If not as specified, repair or replace the generator if necessary.
- Headlights
- Blower motor
- Rear window defroster
Current
1. Verify that the battery is fully charged.
- Charge if necessary.
2. Disconnect the negative battery cable.
3. Connect an ammeter, capable of reading 120 A or above, between generator terminal B and the wiring harness.
4. Connect the negative battery cable.
5. Turn off all electrical loads.
6. Start the engine and increase the engine speed to 2,000-2,500 rpm.
7. Turn the following electrical loads on and verify that the current reading increases.
1. Headlights
2. Blower motor
3. Rear window defroster
- If generator terminal B current does not increase, repair or replace the generator if necessary.
NOTE: Current required for generating power varies with electrical loads applied.
Standard current (Reference)
Measuring conditions
Room temperature: 20 °C {68 °F}
Voltage: 13.5V
Engine hot
Generator Inner Parts
Rotor
1. Measure the resistance between the slip rings using an ohmmeter.
- If not as specified, replace the rotor.
Specification [20 °C {68 °F}]]: 2.4-2.9 ohm
2. Verify that there is no continuity between the slip ring and core using an ohmmeter.
- If there is continuity, replace the rotor.
3. Inspect the slip ring surface condition.
- If the slip ring surface is rough, use a lathe or fine sandpaper to repair it.
Stator coil
1. Inspect for continuity between the stator coil leads using an ohmmeter.
- If there is no continuity, replace the stator.
2. Verify that there is no continuity between the stator coil leads and core using an ohmmeter.
- If there is continuity, replace the stator coil.
Brush
1. Inspect brushes for wear.
- If any brush is worn almost to or beyond the limit, replace all of the brushes.
Standard: 22.5 mm {0.89 in}
Minimum: 5.0 mm {0.20 in}
Brush spring
1. Measure the force of the brush spring using a spring pressure gauge.
2. Read the spring pressure gauge at the brush tip projection of 2 mm {0.079 in}.
- Replace the brush spring if necessary.
Standard force: 4.1-5.3 N {0.42-0.54 kgf, 0.92-1.19 Ibf}
Minimum: 1.7 N {0.17 kgf, 0.38 Ibf}
Rectifier
1. Inspect for continuity of the diodes using an analog circuit tester.
- If not as specified, replace the rectifier.
2. Inspect for continuity of the diodes using an digital circuit tester.
- If not as specified, replace the rectifier.
Bearing
1. Inspect for abnormal noise, looseness, and sticking.
- Replace the bearing if necessary.