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 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
| • | All motor activity will stop and the Transfer Case Lock engaged. |
| • | A default rail to rail shift may be allowed, toggle between 4H and 2H. |
| • | The SERVICE 4WD indicator will be latched 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 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 inspects 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 inspects for a binding sector shaft.
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This step disassembly and overhaul for a binding sector shaft.
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 | |
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, test the encoder channel circuits with a DMM. Are the voltages within the specified range? | 4.8-5.1 V | Go to Step 4 | Go to Step 5 | |
With the ignition in the OFF position, test the encoder signal ground for an open or high resistance. 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. Was the condition found and corrected? | -- | 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 . Was the condition found and corrected? | -- | Go to Step 7 | Go to Step 8 | |
Remove the transfer case for disassembly and repair. Refer to Transfer Case Disassemble . Is the repair complete? | -- | Go to Step 10 | -- | |
8 | Replace the encoder motor. Refer to Transfer Case Motor/Encoder Replacement . Is the replacement complete? | -- | Go to Step 10 | -- |
9 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Is the replacement complete? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | -- | System OK |
