Circuit Description
The transfer case motor is a bi-directional, permanent magnet, DC motor. When energized through motor control A or motor control B, the ground is provided by the opposing motor control circuit, 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 4H, AUTO 4WD, 2H, N, and 4L ranges.
This DTC detects an open in the motor control A or motor control B circuits, or an open motor.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | System voltage is 9-16 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. |
Action Taken When the DTC Sets
| • | The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle. |
| • | All shifting is disabled. |
Conditions for Clearing the DTC
| • | The transfer case shift control module clears the DTC if the condition for setting the DTC no longer exists. |
| • | A history DTC clears 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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This step listens for an audible motor noise when the encoder motor operates. Command both the ON and OFF states. Repeat the commands as necessary.
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This step tests the for a higher than normal resistance in the motor control A and B circuits and through the module.
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This step tests the motor control A circuit for an open or high resistance.
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This step tests the motor control B circuit for an open or high resistance.
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This step tests for continuity across the motor circuit.
Step | Action | Value(s) | 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 encoder motor turn ON and OFF? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
Is the resistance reading greater than the specified value? | 2 ohms | Go to Step 4 | Go to Step 6 | |
Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 5 | |
Test the motor control B circuit harness connector for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 | |
Test for continuity across the motor circuit. Refer to Testing for Continuity in Wiring Systems. Are the resistance readings within the specified range? | 0.5-35 ohms | Go to Step 8 | Go to Step 7 | |
7 | Replace the motor encoder. Refer to Transfer Case Motor/Encoder Replacement . Did you complete the repair? | -- | Go to Step 9 | -- |
8 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Did you complete the repair? | -- | Go to Step 9 | -- |
9 |
Does the DTC set? | -- | Go to Step 2 | System OK |
