Alternator: Testing and Inspection

Generator Test

Slow engine cranking or low specific gravity of battery electrolyte may result from an undercharged battery due to failure in the generator even the charging indicator light is operating normally.

Before beginning generator test in this case, perform the following procedure.

- Make sure that undercharged condition has not been caused by accessories being left on for extended period of time.
- Check drive belt for wear and tension Tension Inspection.
- If battery defect is suspected, refer to Description and Operation Battery Description.
- Inspect all wiring for defects and for tightness and cleanliness of connections. In particular, inspect the battery cable, starting motor leads and ignition ground cable.

No-Load Check

NOTE:

Use fully charged battery.

1) Check for DTC. DTC Check

If there is any DTC, perform trouble shooting for applicable DTC and then clear DTC.
- Trouble shooting: ECM
- DTC clearance: DTC Clearance
2) Turn off all electrical loads (5).
3) Connect voltmeter (3) and ammeter (2) as shown in figure.
4) Start engine and warm it up to normal operating temperature.











5) Run engine around 2,000 rpm and read meters.
- If voltage is higher than standard value, check ground circuit of brushes. Generator Inspection
If brushes are not grounded, replace IC regulator.
- If voltage is lower than standard value, inspect rotor, stator, rectifier, bushings and regulator. Generator Inspection

Specification for generator test (No-load check)
Current: 10 A
Regulated voltage (High): 14.2 - 14.8 V (at 25 °C, 77 °F)
Regulated voltage (Low): 12.5 - 13.1 V (at 25 °C, 77 °F)









Load Check

NOTE:

Use fully charged battery.

1) Connect ammeter in the same way as No-Load Check.
2) Run at engine around 2,000 rpm and turn on the following electrical accessories.
- Headlight (High beam)
- Rear window defogger
- Blower motor (Maximum speed)
3) Read ammeter.

If meter reading is less than 20 A, repair or replace generator.