Output Current Test

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Required Special Tools: 

• MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
• MB992745: V.C.I.-Lite main harness A
• MB992747: V.C.I.-Lite USB cable short
• MB992748: V.C.I.-Lite USB cable long
• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: Vehicles Communication Interface (V.C.I.)
  • MB991827: M.U.T.-III USB Cable
  • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

This test determines whether the generator output current is normal.

1. Always be sure to check the following before the test.
   • Generator installation
   • Battery (Refer to BATTERY TEST ).
     NOTE: The battery should be slightly discharged. The load needed by a fully-charged battery is insufficient for an accurate test.
   • Drive belt tension (Refer to DRIVE BELT TENSION CHECK AND ADJUSTMENT ).
   • Fusible link
   • Abnormal noise from the generator while the engine is running.
2. Turn the ignition switch to the "LOCK" (OFF) position.
3. Disconnect the negative battery cable.
4. Set a clamp-type DC test ammeter to the generator "B" terminal output wire.
   NOTE: Disconnecting the generator output wire and connecting the ammeter may not thoroughly diagnose an output current drop problem because of an insufficient connection between terminal "B" and the output wire.
5. Connect a voltmeter with a range of 0 - 20 volts between the generator "B" terminal and the ground (Connect the positive lead of the voltmeter to the "B" terminal, and then connect the negative lead of the voltmeter to the ground).
6. Reconnect the negative battery cable.
   CAUTION: To prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
7. Connect scan tool (M.U.T.-III) to the data link connector [Refer to MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS ].
8. Leave the hood open.
9. Check that the reading on the voltmeter is equal to the battery voltage.
   NOTE: If the voltage is 0 volt, the cause is probably an open circuit in the wire or fusible link between the generator "B" terminal and the positive battery terminal.
10. Turn the light switch "ON" to turn on headlights and then start the engine.
11. Using the scan tool (M.U.T.-III), select data list item number 2 "Crank angle sensor" in MFI system and check that the engine speed (Refer to DATA LIST REFERENCE TABLE ).
12. Immediately after setting the headlights to high beam and turning the heater blower switch to the high revolution position, increase the engine speed to 2, 500 r/min and read the maximum current output value displayed on the ammeter.

    Limit: 70 percent of normal current output 

    NOTE:

    • For the nominal current output, refer to the Generator Specifications.
    • Because the current from the battery will soon drop after the engine is started, the above step should be carried out as quickly as possible in order to obtain the maximum current output value.
    • The current output value will depend on the electrical load and the temperature of the generator body.
    • If the electrical load is small while testing, the specified level of current may not be output even though the generator is normal. In such cases, increase the electrical load by leaving the headlights turned on for some time to discharge the battery or by using the lighting system in another vehicle, and then test again.
    • The specified level of current also may not be output if the temperature of the generator body or the ambient temperature is too high. In such cases, cool the generator and then test again.
13. The reading on the ammeter should be above the limit value. If the reading is below the limit value and the generator output wire is normal, remove the generator from the engine and check the generator.
14. Run the engine at idle after the test.
15. Turn the ignition switch to the "LOCK" (OFF) position.
16. Disconnect the scan tool (M.U.T.-III) to the data link connector.
17. Disconnect the negative battery cable.
18. Disconnect the ammeter and voltmeter.
19. Connect the negative battery cable.