Lexus GS, SC 1998-06

Alternator

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Diagnosis & Testing



  1. Check that the alternator wiring is in good condition. If the condition is not good, repair or replace the generator wire.
  2.  
  3. Check that there is no abnormal noise from the alternator while the engine is running. If there is abnormal noise, replace the pulley or generator.
  4.  
  5. Check the discharge warning light circuit as follows:


    1. Warm up engine and then turn it off.
    2.  
    3. Switch off all accessories.
    4.  
    5. Turn the ignition switch ON. Check that the discharge warning light is lit.
    6.  
    7. Start the engine. Check that the light goes off.
    8.  
    9. If the light does not go off as specified, troubleshoot the charge warning light circuit.
    10.  

  6.  
  7. Inspect the charging circuit without load, using a battery/alternator tester connected to the charging circuit as per manufacturer-s instructions.

    Click image to see an enlarged view

    Fig. Connect a voltmeter to the charging circuit as shown.

  8.  
  9. If a tester is not available, connect a voltmeter 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 (positive (+) battery terminal for GS 430 and 2006 GS 300).
    6.  
    7. Ground the negative (-) tester probe of the voltmeter.
    8.  

  10.  
  11. Check the charging circuit with the engine running from idling to 2,000 rpm, check the reading on the ammeter and voltmeter. Standard amperage should read 10 amps or less and standard voltage should read 13.2-14.8V at 25°C (77°F) or 13.2-14.0V at 115°C (239°F).
  12.  
  13. If the results are not as specified, replace the alternator assembly.
  14.  
  15. If the battery is not fully charged, the ammeter reading may be more than the standard amperage. In this case, increase electrical load by operating devices such as the wiper motor and rear window defogger. Then, recheck the reading on the ammeter.
  16.  
  17. For the 2JZ-GE engine, if the voltmeter reading is more than standard voltage, replace the voltage regulator.

    Click image to see an enlarged view

    Fig. Checking the continuity between terminals F and B of the voltage regulator.-2JZ-GE engine



    Click image to see an enlarged view

    Fig. Checking the continuity between terminals F and E of the voltage regulator.-2JZ-GE engine

  18.  
  19. For the 2JZ-GE engine, if the voltmeter reading is less than standard voltage, check the voltage regulator as follows:


    1. Using an ohmmeter, check the continuity between terminals F and B.
    2.  
    3. When the positive and negative poles between terminals F and B (or terminals F and E) are exchanged, there is continuity in one way but no continuity in another way.
    4.  
    5. If the continuity is not as specified, replace the regulator.
    6.  
    7. Using an ohmmeter, check the continuity between terminals F and E.
    8.  
    9. If the continuity is not as specified, replace the regulator.

      Click image to see an enlarged view

      Fig. Checking the voltage regulator by grounding terminal F.-1UZ-FE engine

    10.  

  20.  
  21. For the 1UZ-FE engine, if the voltmeter reading is less than standard voltage, check the voltage regulator and alternator as follows:


    1. With terminal F grounded, start the engine and check the voltmeter reading of terminal B.
    2.  
    3. If the voltmeter reading is more than standard voltage, replace the voltage regulator.
    4.  
    5. If the voltmeter reading is less than standard voltage, check the alternator.
    6.  

  22.  
  23. Inspect the charging circuit with load as follows:


    1. With the engine running at 2,000 rpm, turn on the high beam headlights and place the heater blower switch at -HI-.
    2.  
    3. Check the reading on the ammeter. Standard amperage is 30 amps or more.
    4.  
    5. If the ammeter reading is less than standard amperage, replace the alternator.
    6.  
    7. If the battery is fully charged, the indication will sometimes be less than standard amperage. In this case, increase electrical load by operating devices such as the wiper motor and rear window defogger. Then, recheck the reading on the ammeter.
    8.  

  24.  

Installation



1MZ-FE Engine
  1. Install or connect the following:

    Alternator
     
    Alternator harness connectors
     
    Accessory drive belt. Tighten the adjusting lock bolt to 13 ft. lbs. (18 Nm) and the pivot bolt to 41 ft. lbs. (56 Nm).
     
    Negative battery cable
     

  2.  

  1. Install or connect the following:

    Alternator
     
    Alternator harness connectors
     
    Accessory drive belt. Tighten the adjusting lock bolt to 13 ft. lbs. (18 Nm) and the pivot bolt to 41 ft. lbs. (56 Nm).
     
    Negative battery cable
     

  2.  

1UZ-FE & 3UZ-FE Engines
  1. Install or connect the following, as equipped:

    Alternator. Tighten the fasteners to 29 ft. lbs. (39 Nm).
     
    HO2S sensor wiring
     
    Power steering pump oil hose to oil pan
     
    Alternator harness connectors
     
    Power steering pump pulley
     
    Engine under cover
     
    Oil pan protector
     
    Accessory drive belt
     
    Air cleaner inlet
     
    Negative battery cable
     

  2.  

  1. Install or connect the following:

    Alternator. Tighten the fasteners to 29 ft. lbs. (39 Nm).
     
    HO 2 S sensor wiring
     
    Alternator harness connectors
     
    Power steering pump
     
    Engine under cover
     
    Oil pan protector
     
    Accessory drive belt
     
    Air cleaner inlet
     
    Negative battery cable
     

  2.  

2JZ-GE Engine
  1. Install or connect the following:

    Bolt, nut, pipe bracket and alternator. Tighten the fasteners to 30 ft. lbs. (40 Nm).
     
    2 automatic transmission oil cooler pipes to the alternator
     
    Bolt and pipe clamp
     
    Alternator wire clamp to the wire clip on the alternator
     
    Alternator wire
     
    Cap and nut
     
    Alternator connector
     
    Accessory drive belt
     
    Engine under cover
     
    Negative battery cable
     

  2.  

  1. Install or connect the following:

    Bolt, nut, pipe bracket and alternator. Tighten the fasteners to 30 ft. lbs. (40 Nm).
     
    2 automatic transmission oil cooler pipes to the alternator
     
    Bolt and pipe clamp
     
    Alternator wire clamp to the wire clip on the alternator
     
    Alternator wire
     
    Cap and nut
     
    Alternator connector
     
    Accessory drive belt
     
    Engine under cover
     
    Negative battery cable
     

  2.  

3MZ-FE Engines
  1. Install or connect the following:

    Wiring harness clamp bracket with bolt
     
    Temporarily install mounting bolts
     
    Adjust belt with tensioner
     
    Tighten mounting bolts to lower mounting bolt 13ft.lbs. (18 Nm) upper 43 ft. lbs.(58 Nm)
     
    Alternator wire nut, tighten to 7 ft. lbs. (9.8 Nm)
     
    Alternator wire connector
     
    Wiring harness clamp
     
    Battery negative cable
     

  2.  

3UZ-FE Engines



The 2 clamps from cord clips on alternator
 
The nut, bolt, stay and alternator, torque to 29 ft lbs. (39Nm)
 
PS oil hose to #1 oil pan bolt
 
The alternator wire connector from the clamp on cord clip
 
Alternator wire from the clamp on the cord clip
 
The rubber cap and nut and alternator wire
 
The alternator connector
 
PS pulley or pump, torque to 32 ft. lbs (43Nm)
 
Air cleaner inlet
 
Negative battery cable
 
Drive belt
 
Engine undercover (if necessary)
 

Removal



1mz-FE
  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Accessory drive belt
     
    Alternator harness connectors
     
    Alternator
     

  4.  

1uz-FE & 3uz-FE Engines
  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Air cleaner inlet
     
    Accessory drive belt
     
    Oil pan protector
     
    Engine under cover
     
    Power steering pump
     
    Alternator harness connectors
     
    Heated Oxygen (HO 2 S) sensor wiring
     
    Alternator
     

  4.  

2jz-GE
  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Engine under cover
     
    Accessory drive belt
     
    Alternator connector
     
    Cap and nut
     
    Alternator wire
     
    Alternator wire clamp from the wire clip on the alternator
     
    Bolt and pipe clamp
     
    2 automatic transmission oil cooler pipes from the alternator
     
    Bolt, nut, pipe bracket and alternator
     

  4.  

Removal & Installation



1MZ-FE Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Accessory drive belt
     
    Alternator harness connectors
     
    Alternator
     

  4.  

1UZ-FE & 3UZ-FE Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following, as equipped:

    Negative battery cable
     
    Air cleaner inlet
     
    Accessory drive belt
     
    Oil pan protector
     
    Engine under cover
     
    Power steering pump pulley
     
    Alternator harness connectors
     
    Power steering oil hose from oil pan
     
    Heated Oxygen (HO2S) sensor wiring
     
    Alternator
     

  4.  

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable. Wait at least 90 seconds before performing any other work.
     
    Air cleaner inlet
     
    Accessory drive belt
     
    Oil pan protector
     
    Engine under cover
     
    Power steering pump
     
    Alternator harness connectors
     
    Heated Oxygen (HO 2 S) sensor wiring
     
    Alternator
     

  4.  

To install:

  1. Install or connect the following:

    Alternator. Tighten the fasteners to 29 ft. lbs. (39 Nm).
     
    HO 2 S sensor wiring
     
    Alternator harness connectors
     
    Power steering pump
     
    Engine under cover
     
    Oil pan protector
     
    Accessory drive belt
     
    Air cleaner inlet
     
    Negative battery cable
     

  2.  

2JZ-GE Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Engine under cover
     
    Accessory drive belt
     
    Alternator connector
     
    Cap and nut
     
    Alternator wire
     
    Alternator wire clamp from the wire clip on the alternator
     
    Bolt and pipe clamp
     
    2 automatic transmission oil cooler pipes from the alternator
     
    Bolt, nut, pipe bracket and alternator
     

  4.  

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable. Wait at least 90 seconds before performing any other work.
     
    Engine under cover
     
    Accessory drive belt
     
    Alternator connector
     
    Cap and nut
     
    Alternator wire
     
    Alternator wire clamp from the wire clip on the alternator
     
    Bolt and pipe clamp
     
    2 automatic transmission oil cooler pipes from the alternator
     
    Bolt, nut, pipe bracket and alternator
     

  4.  

To install:

  1. Install or connect the following:

    Bolt, nut, pipe bracket and alternator. Tighten the fasteners to 30 ft. lbs. (40 Nm).
     
    2 automatic transmission oil cooler pipes to the alternator
     
    Bolt and pipe clamp
     
    Alternator wire clamp to the wire clip on the alternator
     
    Alternator wire
     
    Cap and nut
     
    Alternator connector
     
    Accessory drive belt
     
    Engine under cover
     
    Negative battery cable
     

  2.  

3gr-Fse Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable. Wait at least 90 seconds before performing any other work.
     
    V-bank cover sub-assembly
     
    Cool air intake duct seal
     
    Left engine room side cover
     
    Engine under cover
     
    Serpentine drive belt
     

  4.  
  5. Remove or disconnect the with pulley compressor by performing the following:
    NOTE
    It is not necessary to completely remove the compressor. With the hoses connected to the compressor, hang the compressor on the vehicle body with a rope.



    Bolt, nut and bracket (AWD)
     
    Magnetic clutch connector
     
    Nut and 3 bolts (2WD); or 2 bolts (AWD)
     
    Stud bolt using an E8 -torx- socket and with pulley compressor
     



    No. 2 idler pulley sub-assembly
     
    Clamp and bolt from alternator
     
    Alternator connector
     
    Rubber cap
     
    Nut and battery cable.
     
    Nut, bolt and alternator bracket
     
    2 mounting bolts and alternator
     

  6.  

To install:

  1. Install or connect the following:

    Alternator and 2 mounting bolts. Torque to 32 ft. lbs. (43 Nm).
     
    Alternator bracket with bolt and nut at the engine. Torque to 15 ft. lbs. (20 Nm).
     
    Battery cable. Tighten the nut to 87 inch lbs. (10 Nm).
     
    Wire harness bracket and clamp to the alternator
     
    Alternator wire to terminal.
     
    Terminal cap
     
    No. 2 idler pulley and cover plate with the bolt. Tighten bolt to 32 ft. lbs. (43 Nm).
     
    With pulley compressor assembly
     
    Serpentine drive belt
     
    Engine under cover
     
    Left engine room side cover
     
    Cool air intake duct seal
     
    V-bank cover sub-assembly
     
    Negative battery cable
     

  2.  

3MZ-FE Engines


Click image to see an enlarged view

Fig. Removing wire harness clamps-3.3L (3MZ-FE)



Click image to see an enlarged view

Fig. Loosening belt tension bolt-3.3L (3MZ-FE)



Click image to see an enlarged view

Fig. Removing alternator bolts-3.3L (3MZ-FE)



Click image to see an enlarged view

Fig. Removing wiring harness clamp from alternator-3.3L (3MZ-FE)

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Remove two wire harness clamps.
     
    Disconnect the alternator connector.
     
    Open the terminal clamp.
     
    Remove the nut, then disconnect the alternator wire.
     
    Loosen mounting bolts to lessen tension of the alternator belt
     
    Remove mounting bolts
     
    Remove the wiring harness clamp bolt.
     

  4.  

 
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