Mazda RX-8 2004-06

Alternator

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Diagnosis & Testing



Current Check
  1. Make sure the battery is fully charged.
  2.  
  3. Make sure the drive belt deflection/tension is within proper specifications. Refer to the Accessory Drive Belt procedures in the Engine Mechanical Section.
  4.  
  5. Disconnect the negative battery cable.
  6.  
  7. Connect a tester capable of reading 120 A or above between alternator terminal B and the wiring harness.
  8.  
  9. Connect the negative battery cable.
  10.  
  11. Turn off all electrical loads.
  12.  
  13. Start the engine.
  14.  
  15. Increase engine speed from 2,000-2,500 rpm.
  16.  
  17. Turn the following electrical loads on and verify that the current reading increases:
    1. Headlights
    2.  
    3. Blower motor
    4.  
    5. Rear window defroster
      NOTE
      Current required for generating power varies with electrical loads applied. For reference value, current possible for power generation (differs according to load). Conditions for check: ambient temperature 69°F (20°C), voltage 13.0-15.0 V, engine warm.



      Click image to see an enlarged view

      Fig. Alternator current check specification table

    6.  

  18.  

Voltage Check
  1. Make sure the battery is fully charged.
  2.  
  3. Make sure the drive belt deflection/tension is within proper specifications. Refer to the Accessory Drive Belt procedures in the Engine Mechanical Section.
  4.  
  5. Turn off all electrical loads.
  6.  
  7. Start the engine and check to be sure that the alternator rotates smoothly without any noise while the engine is running.
  8.  
  9. Measure the voltage at each terminal using a tester and compare with the accompanying table.

    Click image to see an enlarged view

    Fig. Alternator terminal identification



    Click image to see an enlarged view

    Fig. Alternator voltage check specification table

  10.  

Warning Light Check

WARNING
Do not apply direct battery positive voltage to the alternator terminal D, otherwise it could cause damage to the internal parts (power transistor) of the alternator.

  1. Make sure the battery is fully charged.
  2.  
  3. Make sure the drive belt deflection/tension is within proper specifications. Refer to the Accessory Drive Belt procedures in the Engine Mechanical Section.
  4.  
  5. With the ignition switch ON , check that the alternator warning light illuminates. If it does not illuminate, inspect the alternator warning light and the wiring harness.
  6.  
  7. If the alternator warning light and the wiring harness are normal, inspect the PCM.
  8.  
  9. Make sure the alternator warning light turns off after the engine is started. If it does not turn off, check if any one of the following DTCs in the on-board diagnostic system are displayed: P0112, P0113, P2502, P2503, P2504.
  10.  

Removal & Installation



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

    Negative battery cable
     
    Engine cover
     
    Rear engine cross brace
     
    Intake air duct
     
    Accessory drive belt
     
    Electrical connectors from the alternator
     
    Alternator bolts
     
    Alternator

    Click image to see an enlarged view

    Fig. Alternator mounting-1.3L engine

     

  4.  

To install:

Installation is the reverse of the removal procedure, noting the following. Tighten the left side engine cross brace nut to 40 ft. lbs. ( Nm) and the right side nut to 16 ft. lbs.

 
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