GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 21008-A Self-Powered Test Light
    • J 39200 Digital Multimeter

Notice: Do not clean the starter motor parts in a degreasing tank. Soaking parts will dissolve the permanent lubrication and may damage the electrical insulation. This will shorten starter motor life.

Starter Solenoid Inspection


    Object Number: 1030  Size: SH
  1. Inspect the solenoid for grounds using a self-powered test lamp J 21008-A .
  2. If the solenoid does not pass the following tests, install a new solenoid.
  3. 2.1. Connect J 21008-A between the BAT terminal and the metal housing (ground).
    2.2. The lamp should not light, meaning that the terminal is not grounded.
    2.3. Connect J 21008-A between the S terminal and the metal housing.

    The lamp should light.

    2.4. Connect J 21008-A between the M terminal and the S terminal, or connect the test lamp between the M terminal and the metal housing.

    The lamp should light.

    Notice: To prevent overheating of the solenoid pull-in winding, do not leave the winding energized for more than 15 seconds. The current draw will decrease as the winding temperature increases.


    Object Number: 1031  Size: SH
  4. Inspect the hold-in winding and the pull-in winding.
  5. Important: Before testing, the solenoid must be removed from the starter motor, or the field lead must be removed from the terminal on the solenoid.

  6. In order to test both windings, perform the following procedure:
  7. 4.1. Connect a multimeter in series with a 12 V battery positive terminal, and the switch S terminal on the starter solenoid.
    4.2. Connect the J 39200 to the S terminal on the starter solenoid and to the negative battery terminal.
    4.3. Connect the carbon pile (variable resistance) across the battery.
    4.4. Ground the solenoid motor M terminal.
    4.5. Adjust the voltage to 10 V and observe the multimeter reading.
    4.6. The reading should be between 60-85 amperes.
       • A higher multimeter reading means that the winding is shorted or grounded.
       • A lower multimeter reading means that there is excessive resistance in the winding.
    4.7. The J 39200 reads the winding resistance, and measures in tenths of an ohm.
    4.8. Dividing the voltage by the amperes (voltage/amperes), determines coil resistance. Refer to Starter Motor Usage Table.

Drive Inspection

  1. Check pinion teeth for cracks or excessive wear. Replace the drive if these conditions are found.
  2. Inspect the flywheel for similar damage.
  3. Inspect the drive assembly for slipping before disassembling from armature.
  4. Wrap armature in a shop cloth to protect it damage.
  5. Clamp the armature in vise just tight enough to hold firmly.
  6. Use a 12-point deep socket and a torque wrench to turn the pinion.
  7. • If the pinion does not turn freely in the overrunning direction (clockwise), replace the drive.
    • Pinion should lock when turned in the counterclockwise direction and should withstand a torque of 68 N·m (50 lb ft). If the drive pinion slips, replace the drive.
  8. Refer to Starter Motor Disassembly to remove the drive from the armature.

Armature Inspection

  1. Clean all parts by wiping with a dry cloth.
  2. Inspect the bushing or the armature bearing fit in the following locations:
  3. • The end frame
    • The shift lever housing
    • The drive end frame housing (If the bushings or the bearings are damaged, install new ones.)
  4. Lubricate the bushings before assembling the starter motor.
  5. • Avoid over lubrication.
    • Do not lubricate the roller bearings.
    • The roller bearings are permanently lubricated when manufactured.
  6. Inspect the armature shaft for runout or scoring. If the condition of the armature shaft is in doubt, install a new armature.
  7. Inspect the commutator for discolored or uneven conductors.
  8. • Do not turn the commutator on a lathe.
    • Do not undercut the insulation.
    • Clean the commutator with No. 400 grain polishing cloth.
    • Blow away any copper dust.
  9. If the commutator can not be cleaned satisfactorily, install a new armature.

  10. Object Number: 1033  Size: SH
  11. Inspect the armature for short circuits using the following procedure:
  12. • Rotate the armature in a growler.
    • Use a steel strip (such as a hacksaw blade) held on the armature, parallel to the shaft.
    • If a short circuit is detected, the steel strip will vibrate over the area.
    • Consult the growler manufacturer's instructions for more information.
    • Short circuits between the commutator bars can be produced by brush dust or copper dust.
  13. Inspect the armature for opens as follows:
  14. • Look for loose connections where the conductors join the commutator bars.
    • Poor connections cause arcing.
    • Arcing causes burning of the commutator.

    Object Number: 1034  Size: SH
  15. Inspect the armature for grounds with a self-powered test lamp (continuity tester). Use J 21008-A .
  16. • Place one test probe on the commutator.
    • Place the other test probe on the armature core or shaft.
    • If the test lamp lights, the armature is grounded. Replace any grounded or shorted armature.

Brush Holder Assembly Inspection

  1. Inspect the brushes for wear. If the brushes are worn to half the size of a new brush, replace the assembly.
  2. Inspect the holders for dirt or damage. Make sure that the brushes move freely and do not bind in the holders.
  3. Inspect the brush springs for distortion or discoloring.
  4. • Repair any damaged brush springs, as necessary.
    • If the brush springs are weak, bent or discolored, replace the field and frame assembly.

Frame and Field Inspection

  1. Inspect the field coils.
  2. • Look for burned or damaged insulation.
    • Look for damaged connections.
    • Look for loose poles.
    • If the condition of the coils is doubtful, replace the field and frame assembly.

    Object Number: 42120  Size: SH
  3. Inspect the field coils for grounds.
  4. • Connect the two leads from the J 21008-A between the field frame and the field connector.
    • Be sure that the brush ends do not contact the field frame.
    • If the test lamp lights, the field coils are grounded.
    • Install a new field and frame assembly.

    Object Number: 42119  Size: SH
  5. Inspect the field coils for opens.
  6. • Connect the two leads from the J 21008-A between the field connector and each of the positive brushes.
    • If the test lamp does not light at both brushes, then the fields are open.
  7. Inspect the field coils for shorts.
  8. • Shorts are indicated if the starter motor runs poorly after all other inspection procedures are complete.
    • If shorted, replace the frame and field coils as an assembly.