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Component Testing

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Transfer Case Encoder Motor (TCEM) - Actuator Lock, Motor A and Motor B

  1. Remove the encoder motor from transfer case. Using a paint pen or marker, place indexing marks on the encoder motor drive gear and the mounting surface of the encoder motor.
  2. Using a purple probe J 35616-5, attach the red lead from one of the EL-49741  harnesses to the battery positive voltage terminal of the TCEM, pin B.
  3. Using a purple probe J 35616-5, attach the black lead from this same jumper harness to the lock solenoid control terminal of the TCEM, pin C.
  4. Attach a 9 volt battery to this harness (not included). You will hear the encoder motor unlock.
  5. Using a purple probe J 35616-5, attach the red lead from the other EL-49741  jumper harness to the motor control A terminal of the TCEM, pin A.
  6. Using a purple probe J 35616-5, attach the black lead from this same jumper harness to the motor control B terminal of the TCEM, pin D.
  7. Touch the battery terminals of the 9 volt battery to the battery terminals of the jumper harness. This should rotate the encoder motor drive gear in either a clockwise or counterclockwise rotation depending on battery orientation.
    • If the encoder motor drive gear does not rotate, replace the encoder motor.
  8. Using the purple probes J 35616-5, test for between 0.3-40 Ω between the motor control A circuit TCEM X1 pin A and the motor control B circuit TCEM X1 pin D.
    • If greater than the specified range, replace the encoder motor.
    • If less than the specified range, replace the encoder motor.
  9. Using the purple probes J 35616-5, test for greater than 10 Ω between the following circuits and the encoder motor case:
    • Motor control A, TCEM harness X1 pin A.
    • Motor control B, TCEM harness X1 pin D.
      • If outside the specified range, replace the encoder motor.
  10. Using the purple probes J 35616-5, test for greater than 1 M Ω between the motor control A circuit, TCEM X1 pin A and all other pins on the TCEM harness X1 except the motor control B, TCEM X1 pin D.
    • If outside the specified range, replace the encoder motor.
  11. Using the purple probes J 35616-5, test for greater than 1 M Ω between the motor control B circuit, TCEM X1 pin D. and all other pins on the TCEM harness X1 except the motor control A circuit, TCEM X1 pin A.
    • If outside the specified range, replace the encoder motor.
  12. Test the TCCM.

TCCM

  1. Ignition OFF. Disconnect the X1 harness connector at the TCEM.
  2. Ignition ON, engine OFF. Install EL-49742  harness.
  3. Using the purple probes J 35616-4A, connect a test lamp between the motor control A circuit, TCEM X1 pin A and the ground terminal of EL-49742  harness, black terminal.
  4. Using the Transfer Case Motor Control function of the Special Function feature of the scan tool, command the motor forward and reverse. When commanded forward, the test light should illuminate for 10 seconds and turn OFF. When commanded reverse, the test light should turn OFF.
    • If the test light stays ON when commanded OFF, test the motor control A circuit for a short to voltage. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
    • If the test light does not illuminate when commanded ON, test the motor control A circuit for an open or short to ground. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
  5. Using the purple probes J 35616-4A, connect a test lamp between the motor control B circuit, TCEM X1 pin D and the ground terminal of EL-49742  harness, black terminal.
  6. Using the Transfer Case Motor Control function of the Special Function feature of the scan tool, command the motor forward and reverse. When commanded forward, the test light should turn OFF. When commanded reverse, the test light should illuminate for 10 seconds and turn OFF.
    • If the test light stays ON when commanded OFF, test the motor control B circuit for a short to voltage. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
    • If the test light does not illuminate when commanded ON, test the motor control B circuit for an open or short to ground. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
  7. Using the purple probes J 35616-4A, connect a test lamp between the motor control A circuit, TCEM X1 pin A and a good ground.
  8. Using the Transfer Case Motor Control function of the Special Function feature of the scan tool, command the motor forward and reverse. When commanded Forward/Counter CW, the test light should illuminate dimly for 10 seconds and turn OFF. When commanded Reverse/Clockwise, the test light should turn OFF.
    • If the test light stays ON after the 10 seconds, test the motor control A circuit for a short to voltage. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
    • If the test light does not illuminate at all, test the motor control A circuit for an open or short to ground. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
  9. Using the purple probes J 35616-4A, connect a test lamp between the motor control B circuit, TCEM X1 pin D and a good ground.
  10. Using the Transfer Case Motor Control function of the Special Function feature of the scan tool, command the motor forward and reverse. When commanded Forward/Counter CW, the test light should turn OFF. When commanded Reverse/Clockwise, the test light should illuminate dimly for 10 seconds and turn OFF.
    • If the test light stays ON after the 10 seconds, test the motor control B circuit for a short to voltage. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
    • If the test light does not illuminate at all, test the motor control B circuit for an open or short to ground. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
  11. Using the purple probes J 35616-4A, connect a test lamp between the motor control A circuit, TCEM X1 pin A and the B+ terminal of EL-49742  harness, red terminal.
  12. Using the Transfer Case Motor Control function of the Special Function feature of the scan tool, command the motor forward and reverse. When commanded Forward/Counter CW, the test light should illuminate dimly for 10 seconds and turn OFF. When commanded Reverse/Clockwise, the test light should illuminate brightly for 10 seconds and turn OFF.
    • If the test light stays ON after the 10 seconds, test the motor control A circuit for a short to voltage. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
    • If the test light does not illuminate at all, test the motor control A circuit for an open or short to ground. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
  13. Using the purple probes J 35616-4A, connect a test lamp between the motor control B circuit, TCEM X1 pin D and the B+ terminal of EL-49742  harness, red terminal.
  14. Using the Transfer Case Motor Control function of the Special Function feature of the scan tool, command the motor forward and reverse. When commanded Forward/Counter CW, the test light should illuminate brightly for 10 seconds and turn OFF. When commanded Reverse/Clockwise, the test light should illuminate dimly for 10 seconds and turn OFF.
    • If the test light stays ON after the 10 seconds, test the motor control B circuit for a short to voltage. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
    • If the test light does not illuminate at all, test the motor control B circuit for an open or short to ground. If all circuits and connections test normal, reprogram the TCCM. If the DTC continues to set replace the TCCM.
  15. Test the TCEM.
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