Circuit Description
The transfer case motor is a bi-directional, permanent magnet, DC motor. When energized, (through CKTS 1552, 1553, and the ground CKT 150 the module utilize for the motor control), 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 (Adapt), 2H, N, and 4L ranges.
This DTC detects a short to ground on CKT 1552 and 1553.
Conditions for Setting the DTC
| • | The system will test the motor circuits: |
| - | The system checks for unwanted voltage. |
| - | The system supplies voltage on one circuit and reads the voltage back on the other. |
| • | If the system detects a problem with the circuits, the DTC is logged. |
| • | The transfer case shift control module senses a low voltage return on CKT 1552 or 1553 when a high voltage is expected. |
Action Taken When the DTC Sets
| • | All shifting will be disabled. |
| • | The SERVICE indicator (AWD/4WD) lamp will be latched on for the remainder of the current ignition cycle. |
Conditions for Clearing the MIL/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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Listens for an audible motor noise when the encoder operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Tests for a short to ground in the Motor Control A circuit or module.
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Tests for a short to ground in the Motor Control B circuit or module.
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Tests for a higher than normal resistance in the Motor Control A and B circuits and through the module.
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Tests for a short to ground in the encoder motor windings.
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Tests for continuity across the motor circuit. Resistance readings vary depending on the location of brush contact inside the motor assembly.
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Tests Motor Control A circuit for a short to ground.
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Tests Motor Control B circuit for a short to ground.
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Tests Motor Control A and B circuits for an open or high resistance.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Transfer Case Diagnostic System Check performed? | -- | Go to Step 2 | |
Does the Encoder Motor turn ON and OFF? | -- | Go to Diagnostic Aids | Go to Step 3 | |
Is the resistance reading less than the specified value? | 10 K ohms | Go to Step 8 | Go to Step 4 | |
Connect a DMM between the Motor Control B circuit harness connector C1 terminal B and ground at the transfer case. Is the resistance reading less than the specified value? | 10 K ohms | Go to Step 9 | Go to Step 5 | |
Connect a DMM between the Motor Control A and B circuit harness connector C1 terminals A and B at the transfer case. Is the resistance reading less than the specified value? | 2 ohms | Go to Step 6 | Go to Step 10 | |
Test terminals A and B at the transfer case side of the harness for a short to ground. Was the problem found? | -- | Go to Step 11 | Go to Step 7 | |
Test the resistance across the motor circuit. Were the resistance values within the specified range? | 0.5-35 ohms | Go to Step 12 | Go to Step 11 | |
Was the condition found and corrected? | -- | Go to Step 13 | Go to Step 12 | |
Was the condition found and corrected? | -- | Go to Step 13 | Go to Step 12 | |
Was the condition found and corrected? | -- | Go to Step 13 | Go to Step 12 | |
11 | Replace the transfer case encoder motor. Refer to Motor/Encoder Replacement . Are the repairs complete? | -- | Go to Step 13 | -- |
12 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Are the repairs complete? | -- | Go to Step 13 | -- |
13 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
