Diagnostic Instructions
DTC Descriptor
DTC C0374: General System Malfunction
Circuit/System Description
The transfer case shift control module senses rear slip. After several attempts of applying torque to the front wheels, by activating the encoder motor, the transfer case still sees a difference in speed between the front propshaft speed sensor and rear
propshaft speed sensor.
Conditions for Running the DTC
| • | System voltage is 9-18 volts. |
Conditions for Setting the DTC
The transfer case shift control module is unable to correct sensed wheel slip for 10 consecutive seconds.
Action Taken When the DTC Sets
| • | All shifts to Auto mode are disabled. If the current mode is Auto, the system does not allow any further adaptive events, such as correcting slip. |
| • | The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle. |
Conditions for Clearing the DTC
| • | A history DTC clears after 100 consecutive ignition cycles without a fault present. |
| • | Use a scan tool in order to clear history and current DTCs. |
Reference Information
Schematic Reference
Transfer Case Control Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Transfer Case Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information.
Circuit/System Testing
- Take the vehicle on a short test drive.
| ⇒ | With a scan tool, observe the rear and front propshaft speed data parameter in the transfer case data list, while driving. If the RPM value varies or becomes intermittent while driving at a steady speed refer to DTC C0300 for the rear propshaft
and DTC C0305 for the front propshaft. If this checks out go to the next step. |
- Check the motor A and B control circuits for an open, high resistance, short to voltage, and shorts to ground. If nothing is found refer to component testing for checking the motor. If this checks good then go to the next step.
- Remove the encoder motor and with a wrench turn the shift detent shaft in order to engage the clutch and attempt to turn the front propshaft.
| ⇒ | If the front propshaft can be turned then overhaul the transfer case. If the clutch holds firm then replace the module and program. |
Component Testing
- Turn the ignition off and check the motor windings for an internal short to ground inside the motor by probing either the motor A control pin and taking the other lead to ground, or the same can be done using motor B control pin. Motor
control A is pin D and motor B control is pin E.
| ⇒ | If the DMM indicates and short to ground replace the transfer case actuator. If nothing is found continue to the next step. |
- With a DMM check the resistance of the motor windings by probing pin D and pin E on the transfer case actuator.
| ⇒ | The DMM should indicate 0.3-40 ohms, if it does not replace the transfer case actuator and complete the motor learn procedure. If the actuator is within specifications then replace the transfer case control module, program, and complete
the motor learn procedure. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
