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, AUTO 4WD, 2H, N, and 4L ranges. While the transfer case motor is energized the transfer case shift control module also energizes the solenoid for the transfer case lock. The motor lock is disabled (locking action released) and free turning of the transfer case motor and sector shaft is then allowed.
This symptom indicates a short to ground, short to power, or high resistance in the Motor Control A, Motor Control B, or Lock Solenoid Control circuits
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if any DTCs have set.
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Tests for an open or high resistance in the motor windings.
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Tests for an open or high resistance in the lock solenoid windings.
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This step determines if the module is sending voltage through the motor control A circuit.
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This step determines if the module is sending voltage through the motor control B circuit.
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This step determines if the reason voltage is not get from the transfer case shift control module to the encoder motor through motor control A and B circuits is due to an open or high resistance in these circuits.
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This step determines if the proper 8 V reference signal is coming from the transfer case shift control module.
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This step determines if the module is producing the correct voltage through the P, A, B, and C channels.
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Tests the encoder signal ground circuit for an open or high resistance.
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 | Go to Diagnostic System Check |
Were any DTC's identified in the diagnostic system check? | -- | Go to Diagnostic Trouble Codes | Go to Step 3 | |
Is the resistance within the specified values? | 0.8-25 ohms | Go to Step 4 | Go to Step 11 | |
With a DMM measure the resistance of the transfer case lock solenoid, by probing the lock solenoid control circuit and the ignition 1 circuit Is the resistance within the specified values? | 18-25 ohms | Go to Step 5 | Go to Step 11 | |
Is battery voltage present? | -- | Go to Step 6 | Go to Step 7 | |
Was battery voltage present? | -- | Go to Step 8 | Go to Step 7 | |
Test motor control A or motor control B circuits for an open or high resistance. Was the condition found and corrected? | - | Go to Step 13 | Go to Step 12 | |
Was the voltage within the specified range? | 7-9 V | Go to Step 9 | Go to Step 10 | |
Check the voltage on the encoder signals P, A, B, and C on the module side of the harness. Are they within the specified values? | 4.8-5.1 V | Go to Step 10 | Go to Step 12 | |
With the ignition OFF test the encoder signal ground for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Was the condition found and corrected? | -- | Go to Step 13 | Go to Step 11 | |
11 | Replace the encoder motor. Refer to Motor/Encoder Replacement . Is the repair complete? | -- | Go to Step 13 | -- |
12 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Is the repair complete? | -- | Go to Step 13 | -- |
13 |
Does the symptom re-occur? | -- | Go to Step 2 | System OK |
