Alternator and Regulator Circuit Troubleshooting

Special Tools Required 

Alternator, Regulator, Battery, and Starter Tester OTC3131*

*Available through the Acura Tool and Equipment Program, 888-424-6857.

1. Make sure the battery connections are good and the battery is sufficiently charged.
2. Connect the alternator, regulator, battery, and starter tester (OTC3131) to the battery as shown in illustration below.
   NOTE: The probe is used for alternator testing.
   Fig 1: Connecting Alternator, Regulator, Battery, And Starter Tester (OTC3131) To Battery

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
3. Start the engine. Hold the engine speed at 3, 000 RPM with no load (in P or N) until the radiator fan comes on, then let it idle.
4. Do the CHARGING SYSTEM TEST.

   Does the display indicate the voltage is within 13.5-15.1 V and the amperage is 87.5 A or more? 

   YES  -Go to step 5.

   NO  -If the voltage is less than 13.5 V, go to alternator control circuit troubleshooting (see ALTERNATOR CONTROL CIRCUIT TROUBLESHOOTING  ). If the voltage is over 15.1 V and amperage is less than 90 A, replace the alternator (see ALTERNATOR REMOVAL AND INSTALLATION  ) or repair the alternator (see ALTERNATOR OVERHAUL  ).

5. Check the diode condition on the display.

   Does the display indicate GOOD? 

   YES  -The diode is OK. Troubleshooting is completed.

   NO  -If the display indicates BAD, replace the alternator (see ALTERNATOR REMOVAL AND INSTALLATION  ) or repair the alternator (see ALTERNATOR OVERHAUL  ), then retest.

   NOTE: If the display indicates N/A, the diode pattern could not be diagnosed. Repeat the test again. If N/A appears repeatedly, replace the alternator.