Circuit Description
The transfer case encoder is a switch that converts a shaft position, representing a mode or range position, into electrical signals for use by the transfer case shift control module. The encoder houses 4 hall effect sensors that are used for channels P, A, B, and C. These sensors provide a path to ground, when a magnet, which is part of the shift rail, passes over them.
The transfer case shift control module supplies an 8 volt reference and a ground circuit for the encoder hall effect sensors to function.
The transfer case shift control module supplies 5 volts on all the channels. As these channels are pulled to ground, the module can interpret the location of the transfer case shift position.
This DTC detects an open, short to ground, or a short to voltage in the encoder feed circuit, an open in the signal ground circuit, an open, short to ground, or short to voltage in the encoder channel circuits.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | System voltage is 9-16 volts. |
Conditions for Setting the DTC
The transfer case shift control module reads back all high or low voltage on the encoder channel circuits.
Action Taken When the DTC Sets
| • | The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle. |
| • | All motor activity stops and the transfer case lock engages. |
| • | A default rail to rail shift may be allowed, toggle between 4H and 2H. |
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 determines if the transfer case control module is supplying the correct 8 volt reference.
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This step checks for proper voltage on the four encoder signal circuits.
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This step tests for an open or high resistance on the encoder signal ground circuit.
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This step tests the encoder signal circuits for an open, short to ground, or short to power.
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This step checks for a binding sector shaft.
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This step disassembles the transfer case and repairs for a binding sector shaft.
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 | |
Was the voltage within the specified range? | 7-9 V | Got to Step 3 | Go to Step 5 | |
With the encoder motor pigtail connector still disconnected, using a DMM, test the encoder channel circuits. Are the voltages within the specified range? | 4.8-5.1 V | Go to Step 4 | Go to Step 5 | |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 | |
Test the suspect circuits for an open or a short to power. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | |
Remove the motor/encoder and check the sector shaft for a binding condition. Refer to Transfer Case Motor/Encoder Replacement . Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 8 | |
Remove the transfer case for disassembly and repair. Refer to Transfer Case Disassemble . Did you complete the repair? | -- | Go to Step 10 | -- | |
8 | Replace the encoder motor. Refer to Transfer Case Motor/Encoder Replacement . Did you complete the repair? | -- | Go to Step 10 | -- |
9 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Did you complete the repair? | -- | Go to Step 10 | -- |
10 |
Does the DTC set? | -- | Go to Step 2 | System OK |
