Toyota 4Runner 2001-06

Alternator

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Diagnosis & Testing



If a battery/alternator tester is available, connect the tester to the charging circuit recommended by the manufacture's instructions.

If a tester is not available, connect a voltmeter and an ammeter to the charging circuit by doing the following:

  1. Disconnect the wire from terminal B of the alternator and attach to the negative (-) lead of the ammeter.
  2.  



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Fig. Attach the ammeter and voltmeter as shown to test the charging system



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Fig. With the engine running from idle to 2000 rpm, the readings should be as shown

  1. Connect the positive (+) lead of the ammeter to terminal B of the alternator.
  2.  
  3. Connect the positive (+) lead of the voltmeter to terminal B of the alternator.
  4.  
  5. Ground the negative (-) lead of the voltmeter.
  6.  
  7. With the engine running from idle to 2000 rpm, check the reading on the ammeter and voltmeter. The standard amperage should be 10 amps or less; standard voltage cold is 13.9-15.1 volts, and 13.5-14.3 volts hot. If the reading is greater than standard voltage, replace the regulator.
  8.  
  9. If the reading is less than the standard voltage, check the regulator and alternator:
  10.  
  11. With terminal F grounded, start the engine and check the voltmeter reading of terminal B .
  12.  



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Fig. With terminal F grounded, start the engine and check the voltmeter reading of terminal B



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Fig. Note whether the reading is above or below the standard voltage

  1. If the voltmeter reading is more than the standard voltage, replace the regulator.
  2.  
  3. If the voltmeter reading is less than standard voltage, the alternator may be faulty.
  4.  
  5. With the engine running at 2000 rpm turn on the high beam headlights and place the heater switch on high.
  6.  
  7. Check the reading on the ammeter. It should be 30 amps or more.
  8.  



Click image to see an enlarged view

Fig. The ammeter reading should be above 30 amps

  1. If the ammeter reading is less than the standard amperage, replace the alternator.
  2.  



Click image to see an enlarged view

Fig. If the ammeter reading is below the 30 amps, replace the alternator

If the battery is fully charged, the indication will sometimes be slightly less than the standard amperage.


NOTE
If a battery/alternator tester is available, connect the tester to the charging circuit recommended by the manufacture's instructions.

If a tester is not available, connect a voltmeter and an ammeter to the charging circuit by doing the following:

  1. Disconnect the wire from terminal B of the alternator and attach to the negative ( - ) lead of the ammeter.

    Click image to see an enlarged view

    Fig. Attach the ammeter and voltmeter as shown to test the charging system

  2.  
  3. Connect the test lead from the positive (+) terminal of the ammeter to terminal B of the alternator
  4.  
  5. Connect the positive (+) lead of the voltmeter to terminal B of the alternator.
  6.  
  7. Ground the negative (-) lead of the voltmeter.
  8.  
  9. With the engine running from idle to 2000 rpm, check the reading on the ammeter and voltmeter. The standard amperage should be 10 amps or less; standard voltage cold is 13.7-14.7 volts, and 13.2-14.0 volts hot. If the reading is greater than standard voltage, replace the regulator.
  10.  
  11. If the reading is less than the standard voltage, check the regulator and alternator:

    Click image to see an enlarged view

    Fig. With terminal F grounded, start the engine and check the voltmeter reading of terminal B



    Click image to see an enlarged view

    Fig. Note whether the reading is above or below the standard voltage

  12.  
  13. If the voltmeter reading is more than the standard voltage, replace the regulator.
  14.  
  15. If the voltmeter reading is less than standard voltage, the alternator may be faulty.
  16.  
  17. With the engine running at 2,000 rpm, turn on the high beam headlights and place the heater switch on high.
  18.  
  19. Check the reading on the ammeter. It should be 30 amps or more.

    Click image to see an enlarged view

    Fig. The ammeter reading should be above 30 amps

  20.  
  21. If the ammeter reading is less than the standard amperage, replace the alternator.
    NOTE
    If the battery is fully charged, the indication will sometimes be slightly less than the standard amperage.



    Click image to see an enlarged view

    Fig. If the ammeter reading is below the 30 amps, replace the alternator

  22.  

Removal



2.7L

Remove or disconnect the following:



Negative battery cable
 
Alternator wiring
 
Alternator lockbolt, pivot bolt, nut and adjusting bolt
 
Drive belt
 
Wiring harness with the clip
 
Alternator

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Fig. Exploded view of the alternator and drive belt-2.7L 4Runner



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Fig. Locations of the adjusting, pivot and lockbolts-2.7L 4Runner

 

3.4L Engine
  1. Remove or disconnect the following:

    Negative battery cable
     
    Alternator wiring
     
    Alternator locknut, pivot bolt, nut and adjusting bolt
     
    Drive belt
     
    Alternator

    Click image to see an enlarged view

    Fig. Exploded view of the alternator and drive belt-3.4L 4Runner



    Click image to see an enlarged view

    Fig. Locations of the adjusting and pivot bolts and the locknut-3.4L 4Runner

     

  2.  

Removal & Installation



1gr-FE Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the engine appearance cover.
  4.  
  5. Remove the engine undercover.
  6.  
  7. While releasing the belt tension by turning the belt tensioner counterclockwise, and remove the belt from the belt tensioner and alternator.
  8.  
  9. Disconnect the positive battery cable and remove the battery.
  10.  
  11. Remove the alternator wiring harness support bolt from the frame.
  12.  
  13. Disconnect the wiring from the back of the alternator.
  14.  
  15. Remove the 2 bolts for the wiring harness clamp from the alternator.
  16.  
  17. Remove the alternator mounting bolts.
  18.  
  19. Remove the alternator.

    Click image to see an enlarged view

    Fig. Location of the frame side wiring support bolt (top); Wiring harness mounting bolt locations (middle); Alternator mounting bolts (bottom)-4.0L (1GR-FE) Engine

  20.  

To install:

  1. Place the alternator into position and install the mounting bolts. Tighten both bolts to 32 ft. lbs. (43 Nm).
  2.  
  3. Install the wiring harness clamp to the alternator. Tighten the bolts to 71 inch lbs. (8 Nm).
  4.  
  5. Connect the wiring harness to the alternator. Tighten the nut for terminal B to 7 ft. lbs. (9.8 Nm).
  6.  
  7. Install the remaining bolt for the wiring harness support and tighten to 71 inch lbs. (8 Nm).
  8.  
  9. Install the battery.
  10.  
  11. While turning the belt tensioner counterclockwise, align with its holes, and then insert a bar into the holes to hold the belt tensioner. Install the belt over the alternator pulley and tensioner. While turning the belt tensioner counterclockwise, remove the bar.
  12.  
  13. Install the engine undercover and tighten the mounting bolts to 21 ft. lbs. (29 Nm).
  14.  
  15. Install the engine appearance cover and tighten the two nuts to 66 inch lbs. (7.5 Nm).
  16.  
  17. Connect the battery cables.
  18.  

2UZ-FE Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the 11 clips and radiator upper support seal.
  4.  
  5. Loosen the belt tension by turning the belt tensioner counterclockwise, and remove the accessory drive belt.
  6.  
  7. Remove the engine cooling fan. Separate the oil cooler hose, remove the fan shroud and mounting nuts. Lift the fan and fan shroud out as an assembly.
  8.  
  9. Remove the power steering pump.
  10.  
  11. Remove the terming cap and nut and disconnect the alternator wire.
  12.  
  13. Disconnect the alternator wire clamp from the clip on the alternator.
  14.  
  15. Remove the alternator mounting bolt and nuts.
  16.  
  17. Remove the alternator nuts.

    Click image to see an enlarged view

    Fig. Alternator wire, mounting bolt and nuts location-4.7L (2UZ-FE) Engine

  18.  

To install:

  1. Place the alternator into position and install the mounting bolt and nuts. Tighten the bolt 29 ft. lbs. (39 Nm). Tighten the M10 nut to 29 ft. lbs. (39 Nm) and M8 nut to 11 ft. lbs. (16 Nm).
  2.  
  3. Connect the alternator wire and tighten the nut to 86 inch lbs. (9.8 Nm). Install the rubber cap over the terminal and wire into the cord clip.
  4.  
  5. Install the power steering pump.
  6.  
  7. Install the fan and shroud into the vehicle as an assembly. Tighten the fan nuts to 21 ft. lbs. (29 Nm) and tighten the fan shroud bolts to 44 inch lbs. (5 Nm).
  8.  
  9. Set the accessory drive belt to everything except the top idler pulley. Loosen the accessory drive belt by turning the belt tensioner counterclockwise. Then install the drive belt over the idler pulley and release the tensioner.
  10.  
  11. Install the radiator upper support seal clips.
  12.  
  13. Connect the negative battery cable.
  14.  

5VZ-FE Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the wiring at the back of the alternator. Lift the rubber boot; remove the nut from the external terminal and the wire.
  4.  



Click image to see an enlarged view

Fig. Exploded view of the alternator and drive belt-5VZ-FE Engine



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Fig. Locations of the adjusting and pivot bolts and the locknut

  1. Loosen the alternator locknut, pivot bolt, nut and adjusting bolt.
  2.  
  3. Push the alternator towards the engine and remove the belt.
  4.  
  5. Remove the alternator lockbolt, pivot bolt, and nut.
  6.  
  7. Remove the alternator.
  8.  

To install:

  1. Place the alternator into position and loosely install the pivot and adjusting bolts.
  2.  
  3. Install the drive belt; adjust it to the proper tension. Tighten the locknut 25 ft. lbs. (33 Nm) and the pivot bolt 38 ft. lbs. (51 Nm).
  4.  
  5. Connect the wire to the terminal and install the nut and tighten. Fit the rubber boot over the terminal. Attach the wire harness connector.
  6.  
  7. Connect the negative battery cable.
  8.  

  1. Remove or disconnect the following:

    Negative battery cable
     
    Alternator wiring
     
    Alternator locknut, pivot bolt, nut and adjusting bolt
     
    Drive belt
     
    Alternator
     

  2.  


    Click image to see an enlarged view

    Fig. Exploded view of the alternator and drive belt-3.4L engine



    Click image to see an enlarged view

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


To install:

Install or connect the following:



Alternator
 
Drive belt. Tighten the locknut 25 ft. lbs. (33 Nm) and the pivot bolt 38 ft. lbs. (51 Nm).
 
Alternator wiring
 
Negative battery cable
 

  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the wiring at the back of the alternator. Lift the rubber boot; remove the nut from the external terminal and the wire.

    Click image to see an enlarged view

    Fig. Exploded view of the alternator and accessory drive belt-3.4L (5VZ-FE) Engine



    Click image to see an enlarged view

    Fig. Locations of the adjusting and pivot bolts and the locknut

  4.  
  5. Loosen the alternator locknut, pivot bolt, nut and adjusting bolt.
  6.  
  7. Push the alternator towards the engine and remove the belt.
  8.  
  9. Remove the alternator lockbolt, pivot bolt, and nut.
  10.  
  11. Remove the alternator.
  12.  

To install:

  1. Place the alternator into position and loosely install the pivot and adjusting bolts.
  2.  
  3. Install the accessory drive belt; adjust it to the proper tension. Tighten the locknut 25 ft. lbs. (33 Nm) and the pivot bolt 38 ft. lbs. (51 Nm).
  4.  
  5. Connect the wire to the terminal and install the nut and tighten. Fit the rubber boot over the terminal. Attach the wire harness connector.
  6.  
  7. Connect the negative battery cable.
  8.  

 
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