Alternator and Regulator Circuit Troubleshooting

Special Tools Required 

Alternator, Regulator, Battery & Starter Tester OTC3131

Available through the Honda Tool and Equipment Program 888-424-6857

1. Make sure the battery connections are good, and that the battery is sufficiently charged and in good condition (see BATTERY TEST ).
2. Connect the alternator, regulator, battery & starter tester (OTC3131) to the battery as shown below.
   NOTE: The probe is used for alternator testing.
   Fig 1: View Of Alternator, Regulator, Battery & Starter Tester (OTC3131)

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

   Does the display Indicate voltage within 13.5-15.1 V and amperage 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. If the voltage is over 15.1 V and amperage is less than 87.5 A, replace the alternator (see DRIVE BELT AUTO-TENSIONER AIR BLEEDING  ) 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 complete.

   NO  - If the display indicate BAD, replace the alternator (see DRIVE BELT AUTO-TENSIONER AIR BLEEDING  ) or repair the alternator (see ALTERNATOR OVERHAUL  ), then retest. If the display indicate HI A, diode pattern could not be diagnosed. Run test again. If test is incomplete, use multimeter to perform further pinpoint testing, 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.