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 4H, 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 Setting the DTC
| • | The system will test 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 problem 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
| • | All shifting will be disabled. |
| • | The SERVICE 4WD indicator lamp will be commanded on 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 no longer exists. |
| • | 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 number(s) below refer to the step number(s) on the diagnostic table.
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Listen for an audible motor noise when the transfer case 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 | ||||
1 | Was the Transfer Case Diagnostic System Check performed? | -- | Go to Step 2 | |
Does the transfer case encoder motor turn ON and OFF? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
Does the resistance measure 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 the resistance across the motor circuit. Were the resistance readings within the specified range? | 0.5-35 ohms | Go to Step 8 | Go to Step 7 | |
7 | Replace the encoder motor. Refer to Transfer Case Motor/Encoder Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
8 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
