Toyota Tacoma 2002-06

Alternator

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Diagnosis & Testing



Alternator Load Test
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Connect a voltmeter and ammeter to the charging circuit as follows: .
    1. Disconnect the wire from terminal B of the alternator, and connect it to the negative (-) tester probe of the ammeter.
    2.  
    3. Connect the positive (+) tester probe of the ammeter to terminal B of the alternator.
    4.  
    5. Connect the positive (+) tester probe of the voltmeter to terminal B of the alternator.
    6.  
    7. Ground the negative (-) tester probe of the voltmeter.
    8.  

  4.  
  5. With the engine running at 2,000 rpm, turn on the high beam headlights and set the heater blower switch to HI.
  6.  
  7. Check the reading on the ammeter. Standard amperage: 30 A or more
  8.  
  9. If the ammeter reading is less than the standard amperage, repair the alternator.
  10.  

Alternator No-Load Test
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Connect a voltmeter and ammeter to the charging circuit as follows: .
    1. Disconnect the wire from terminal B of the alternator, and connect it to the negative (-) tester probe of the ammeter.
    2.  
    3. Connect the positive (+) tester probe of the ammeter to terminal B of the alternator.
    4.  
    5. Connect the positive (+) tester probe of the voltmeter to terminal B of the alternator.
    6.  
    7. Ground the negative (-) tester probe of the voltmeter.
    8.  

  4.  
  5. With the engine running from idling to 2,000 rpm, check the reading on the ammeter and voltmeter.
  6.  
  7. With no load on the system, the amperage should be 10 A or less, and the voltage should be 13.2-14.0 volts.
  8.  
  9. If the voltmeter reading is more than the standard voltage, replace the voltage regulator.
  10.  
  11. If the voltmeter reading is less than the standard voltage, check the voltage regulator and alternator.

    Click image to see an enlarged view

    Fig. Connecting voltmeter and ammeter for alternator testing

  12.  

Removal & Installation



On some models, the alternator is mounted very low on the engine. On these models, it may be necessary to remove the gravel shield and work from beneath the vehicle in order to gain access to the alternator. Replacing the alternator while the engine is cold is recommended.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Disconnect the alternator wiring.
  6.  
  7. Remove the drive belt.
  8.  
  9. Remove the alternator retaining bolts.
  10.  
  11. Remove the alternator from the vehicle.
  12.  

To install:

  1. Installation is the reverse of the removal procedure.
  2.  
  3. On the 2.4L and 2.7L engines, tighten the locknut to 21 ft. lbs. (29 Nm) and the pivot bolt to 43 ft. lbs. (59 Nm).
  4.  
  5. On the 3.4L engine, tighten the locknut 25 ft. lbs. (33 Nm) and the pivot bolt 38 ft. lbs. (51 Nm).

    Click image to see an enlarged view

    Fig. Locations of the adjusting, pivot and lockbolts-2.4L and 2.7L (3RZ-FE/M) engines



    Click image to see an enlarged view

    Fig. Locations of the adjusting and pivot bolts and the locknut-3.4L Engine

  6.  

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the V bank cover.
  6.  
  7. Remove the radiator support to frame seal, left side.
  8.  
  9. Remove the radiator fan shroud.
  10.  
  11. Disconnect the alternator harness wiring.
  12.  
  13. Remove the drive belt.
  14.  
  15. Remove the alternator retaining bolts.
  16.  
  17. Remove the alternator from the vehicle.
  18.  

To install:

  1. Installation is the reverse of the removal procedure.
  2.  
  3. Tighten the alternator retaining bolts to 32 ft. lbs. (43 Nm.).
  4.  

On some vehicles, the alternator is mounted very low on the engine. It may be necessary to remove the gravel shield and work from beneath the vehicle in order to gain access to the alternator. Replacing the alternator while the engine is cold is recommended.

 
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