Circuit Description
The transfer case motor is a bi-directional, permanent magnet, D.C. motor. When energized, through motor control A or motor control B, the ground is provided by the opposing motor control circuit and then grounded through the transfer case shift control module ground circuit, the motor, through a series of gears, rotates a shaft which moves the mode and range forks to shift the transfer case between the following modes:
| • | AWD |
| • | 4LO |
| • | N |
This DTC detects an open, short to voltage or short to ground in the motor control A or motor control B circuits, or an open, or short to ground inside the motor.
Conditions for Running the DTC
| • | Ignition is ON. |
| • | System voltage is 9-18 volts. |
Conditions for Setting the DTC
| • | The system tests the motor circuits by checking for unwanted voltage. |
| • | Then, the system supplies voltage on each of the motor circuits and reads the voltage back on the other circuit. |
| • | If the system detects a condition with the circuits, the DTC is logged. The transfer case shift control module senses a low voltage return in the motor control A or motor control B circuits when a high voltage is expected. |
| • | The fault must remain current for 1.2 seconds to set the DTC. |
Action Taken When the DTC Sets
| • | All shifting is disabled. |
| • | The SERVICE 4WD indicator will remain illuminated for the remainder of the current ignition cycle. |
Conditions for Clearing the DTC
| • | The transfer case shift control module will clear the DTC if the condition for setting the DTC is not currently present. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
| • | History DTCs can be cleared using a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Tests motor A driver high for proper operation.
-
Tests motor B driver high for proper operation.
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Tests motor A driver low for proper operation.
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Tests motor B driver low for proper operation.
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Tests motor control A and motor control B circuits for being shorted together.
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Tests motor control A for a short to ground, short to voltage, open, or high resistance.
-
Tests motor control B for a short to ground, short to voltage, open, or high resistance.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Transfer Case Control Schematics Connector End View Reference: Transfer Case Control Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Transfer Case? | -- | Go to Step 2 | |
Does the DMM indicate battery voltage? | -- | Go to Step 3 | Go to Step 7 | |
Does the DMM indicate battery voltage? | -- | Go to Step 4 | Go to Step 8 | |
Does the DMM make an audible tone indicating continuity? | -- | Go to Step 5 | Go to Step 7 | |
Does the DMM make an audible tone indicating continuity? | -- | Go to Step 6 | Go to Step 8 | |
With a DMM, check motor control A and motor control B circuits for being shorted together. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 | |
With a DMM, check the motor control A circuit for a short to ground, short to voltage, open, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 | |
With a DMM, check the motor control B circuit for a short to ground, short to voltage, open, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 | |
9 | Replace the encoder motor. Refer to Transfer Case Encoder Motor Replacement . Did you complete the repair? | -- | Go to Step 11 | -- |
10 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Did you complete the repair? | -- | Go to Step 11 | -- |
11 |
Does the DTC set? | -- | Go to Step 2 | System OK |
