Cutlass Supreme V6-191 3.1L VIN M SFI (1997)
Alternator: Diagnostic Trouble Code Tests and Associated Procedures
System Diagnosis - CS-130 Generator
TOOL REQUIRED:
J 39200 Digital MultiMeter
To diagnose the CS 130 generator, use the following procedure:
1. Turn the ignition switch "ON" without starting the engine.
2. Using the J 39200, measure and record the battery voltage. The charge indicator should be on. If the indicator is not on, disconnect the generator
electrical connector and ground the "L" terminal in the electrical connector.
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If the indicator lights, repair or replace the generator.
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If the indicator does not light, locate and repair open circuit between grounding lead and ignition switch. The charge indicator bulb may be
burned out.
3. With ignition switch "ON" and engine running, the charge indicator lamp should be off.
4. If the lamp is not off, turn the engine "OFF" and disconnect the harness connector from the generator.
5. Turn the ignition "ON" and start the engine.
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If the charge indicator lamp does not light, repair or replace the generator.
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If the charge indicator lamp is still lit, check for a "grounded" "L" terminal wire in the harness.
6. With the ignition switch "ON" and the engine not running, connect the J 39200 from ground to the generator connector "L" terminal. This terminal
should have battery voltage.
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If low or 0 volts is indicated, high resistance or an open exists in the circuit.
7. Connect the J 39200 from ground to the generator output "BAT" terminal. This reading should also be very close to battery voltage.
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If low or 0 volts is indicated, high resistance or an open exists in the circuit.
8. Reconnect the wiring harness connector to the generator. Start and run the engine at a moderate speed (above 1000 RPM), with the electrical
loads and accessions "OFF".
9. Measure the voltage across the battery.
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If the voltage is above 16 volts, replace the generator.
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If the voltage is below the battery voltage as in step 2, inspect the circuit between the generator output terminal and the battery for chafing,
corrosion, or breaks. If no problems are found, replace the generator.
10. If a battery/starter/charging system tester is used to test the charging system, follow the manufacturer's instructions and proceed to step 13. If a
battery/starter/charging system tester is not available, proceed to step 11.
11. Disconnect the battery negative cable.
12. Disconnect the wiring harness from the generator output "BAT" terminal.
13. Install an ammeter between the generator output "BAT" terminal and the engine wiring harness.
Important
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Insulate the ammeter to generator and wiring harness connections to make sure that there is no contact to any exposed metal surfaces that could
potentially cause a short.
14. Reconnect the battery negative cable.
15. Start and run engine at moderate speed (2500 RPM minimum).
16. Turn all of the vehicle accessories "ON". Load the battery with a carbon pile to obtain the maximum generator output reading while maintaining a
reading of 13 volts or above.
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If the amperage reading was more than 15 amperes less than the rated Output (refer to "Generator Usage Chart"), replace the generator.
System Diagnosis - Generator
When the charging system is operating normally, the charge indicator lamp will come on when the ignition switch is turned on and will go out when the
engine starts. If the lamp operates abnormally, or if an undercharged or overcharged battery condition occurs, diagnose and repair the charging system.
Remember that an undercharged battery is often caused by accessories being left on overnight, or by a rear compartment or instrument panel
compartment lamp that stays on.
Noise from a generator may be caused by:
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a loose drive pulley.
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loose mounting bolts.
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worn or dirty bearings.
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a faulty diode.
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a faulty stator.
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brush/slip ring friction.
Important
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To avoid damage to electrical equipment, observe the following precautions:
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Do not reverse connections to the generator.
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Do not short across, or ground any of the terminals in the charging circuit, except as directed by the instructions.
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Never disconnect the output terminal while the generator is operating.
