Circuit Description
The transfer case shift control module controls the engagement and disengagement of the front axle by grounding (engaging) CKT 1570. The front axle will be disengaged in 2H and neutral only, it should be engaged in all other modes. This DTC detects a shorted actuator, a short to 12 V on CKT 1570.
Conditions for Setting the DTC
| • | The system will try to engage the front axle. If it can not engage the front axle, the system will not attempt it again during that ignition cycle. |
| • | The transfer case shift control module reads back the front axle output as a high voltage when a low voltage is expected. |
Action Taken When the DTC Sets
| • | All shifting for 4WD and AUTO (Adapt) mode 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
| • | 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 cycle 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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This test will determine if CKT 1570 is shorted to voltage.
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This test will determine if whether the short to voltage in CKT 1570 is the result of an internal short to power within the transfer case shift control module.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Transfer Case Diagnostic System Check performed? | -- | Go to Step 2 | |
Is the voltage reading greater than the specified value? | 0 V | Go to Step 4 | Go to Step 3 | |
3 | Replace the front axle actuator. Refer to Vacuum Actuator Replacement in Front Drive Axles. Is the repair complete? | -- | Go to Step 7 | -- |
Is the voltage reading greater than the specified values? | 0 V | Go to Step 5 | Go to Step 6 | |
5 | Repair short to voltage in CKT 1570. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 7 | -- |
6 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Is the action complete? | -- | Go to Step 7 | -- |
7 |
Have all the ATC components been reconnected and properly mounted? | -- | Go to Step 8 | -- |
8 | Clear all the ATC DTCs. Have all the ATC DTCs been cleared? | -- | -- |
