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 on circuits 1552 and 1553, an open motor.
Conditions for Setting the DTC
| • | The system will test the motor circuits by checking for unwanted voltage. |
| • | The system supplies voltage on the Motor A circuit and reads the voltage back on the Motor B circuit. |
| • | The transfer case shift control module senses no voltage return on circuits 1552 or 1553. |
| • | If the system detects a problem with the circuits, the DTC is logged. |
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 | |
2 |
Are the terminals damaged or corroded? | -- | Go to Step 8 | Go to Step 3 |
3 | Test the encoder motor for an internal open or high resistance. Was the encoder motor within the specified values? | 0.5-35 ohms | Go to Step 4 | Go to Step 7 |
Is the resistance measured within the specified values? | 0-2 ohms | Go to Step 5 | Go to Step 9 | |
Measure the resistance between the transfer case shift control module harness connector C2 terminal B and the encoder motor harness connector terminal B. Is the resistance measured within the specified values? | 0-2 ohms | Go to Step 6 | Go to Step 10 | |
6 | Replace the transfer case shift control module . Refer to Transfer Case Shift Control Module Replacement . Is the repair complete? | -- | Go to Step 11 | -- |
7 | Replace the transfer case encoder motor. Refer to Motor/Encoder Replacement . Are the repairs complete? | -- | Go to Step 11 | -- |
8 | Repair the harness connector. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 11 | -- |
9 | Repair open in CKT 1552. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 11 | -- |
10 | Repair open in CKT 1553. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 11 | -- |
11 |
Have all the ATC components been reconnected and properly mounted? | -- | Go to Step 12 | -- |
12 | Clear all ATC DTCs. Have all the ATC DTCs been cleared? | -- | -- |
