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 a short to ground on circuits 1552 and 1553, or a shorted 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 a low voltage return on circuits 1552 or 1553 when a high voltage is expected.
- 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 AWD/4WD lamp will be latched on for the remainder of the current ignition cycle. |
Conditions for Clearing the MIL/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. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Transfer Case Diagnostic System Check performed? | -- | ||
2 |
Is the resistance reading less than the specified value? | OL | ||
3 | Measure the resistance between the shift control module connector C2 terminal A and ground. Is the resistance reading less than the specified value? | OL | ||
4 | Measure the resistance between the shift control module connector C2 terminal B and ground. Is the resistance reading less than the specified value? | OL | ||
5 |
Is the resistance reading within the specified values? | 0.5-35 ohms | ||
6 | Replace the transfer case shift control module. Refer to Transfer Case Control Module Replacement. Are the repairs complete? | -- | -- | |
7 | Replace the transfer case encoder motor. Refer to Motor/Encoder Replacement. Are the repairs complete? | -- | -- | |
8 | Repair a short between CKTs 1552 and 1553. Refer to Wiring Repairs in Electrical Diagnosis. Are the repairs complete? | -- | -- | |
9 | Repair a short to ground in CKT 1552. Refer to Wiring Repairs. Are the repairs complete? | -- | -- | |
10 | Repair a short to ground in CKT 1553. Refer to Wiring Repairs. Are the repairs complete? | -- | -- | |
11 | Reconnect and properly mount all the transfer case components. Are all the transfer case components reconnected and properly mounted? | -- | -- | |
12 | Clear all the ATC codes. Are all the ATC codes cleared? | -- | -- |
