Circuit Description
The transfer case encoder motor is a permanent magnet D.C. motor and gear reduction assembly. The encoder motor is controlled with a Pulse Width Modulated (PWM) circuit within the transfer case shift control module. This circuit consists of a power supply relay (Motor A) circuit that supplies voltage to the motor through CKT 1552. The Motor B circuit (CKT 1553) is a PWM driver that varies the duty cycle to control the amount of current through the motor to ground.
This DTC detects an open ground circuit 750.
Conditions for Setting the DTC
The system test the motor circuits:
| • | First, the system checks for unwanted voltage. |
| • | Then, the system supplies voltage on each of the motor circuits and reads the voltage back on the other circuit. |
| • | After the system checks for opens and shorts on the motor circuits, its applies voltage to the motor and the voltage on the ground circuit. |
| • | If the system detects a high voltage return on the ground circuit, the DTC is logged. The transfer case shift control module senses a high voltage return on circuit 750 (connector C2 terminal C) when a low voltage is expected. |
Action Taken When the DTC Sets
| • | All clutch activation (slip control) 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 DTC
| • | Current DTC |
| The transfer case shift control module will clear the DTC if the condition for setting the DTC no longer exists. |
| • | History DTC |
| - | Once 100 consecutive ignition cycles without a fault present. |
| - | A scan tool CLEAR CODES command. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Transfer Case Diagnostic System Check performed? | -- | Go to Step 2 | |
Is the resistance reading within the specified values? | 0-2 ohms | Go to Step 4 | Go to Step 3 | |
3 | Repair a loose or open in ground CKT 750 between the transfer case shift control module and splice pack SP 204. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 5 | -- |
4 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement Is the repair complete? | -- | Go to Step 5 | -- |
5 |
Have all the ATC components been reconnected and properly mounted? | -- | Go to Step 6 | -- |
6 | Clear all ATC DTCs. Have all the ATC DTCs been cleared? | -- | -- |
