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 CKTs 1552 and 1553.
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 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. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Transfer Case Diagnostic System Check performed? | -- | Go to Step 2 | |
2 |
Is the resistance reading less than the specified value? | OL | Go to Step 8 | Go to Step 3 |
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 | Go to Step 9 | Go to Step 4 |
4 | Measure the resistance between the transfer case shift control module connector C2 terminal B and ground. Is the resistance reading less than the specified value? | OL | Go to Step 10 | Go to Step 5 |
5 | Test the resistance across the motor circuit. Were the resistance values within the specifed range? | 0.5-35 ohms | Go to Step 6 | Go to Step 7 |
6 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Are the repairs 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 a short between CKTs 1552 and 1553. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 11 | -- |
9 | Repair a short to ground in CKT 1552. Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 11 | -- |
10 | Repair a short to ground in CKT 1553. Refer to Wiring Repairs.Refer to Wiring Repairs in Wiring Systems. Are the repairs complete? | -- | Go to Step 11 | -- |
11 | Reconnect and properly mount all the transfer case components. Are all the transfer case components reconnected and properly mounted? | -- | Go to Step 12 | -- |
12 | Clear all the ATC DTCs. Are all the ATC DTCs cleared? | -- | -- |
