C0305

DTC C0305

Circuit Description
The front propshaft speed sensor is a permanent magnet generator. The permanent magnet generator produces a pulsing AC voltage. The AC voltage level and number of pulses increases as speed increases. The transfer case shift control module converts the pulsating AC voltage to a propshaft RPM which is used for calculations, and to monitor the difference between the front and rear propshaft speed. It is also used in the AUTO 4WD mode of operation to determine the amount of slip and the percent of torque to apply to the front axle. The propshaft RPM can be displayed with a scan tool.

This DTC detects an open, short to ground, short to voltage or faulty sensor.

DTC Descriptor
This diagnostic procedure supports this DTC:
DTC C0305 Front Speed Sensor Malfunction

Conditions for Running the DTC
^ The ignition is ON.
^ The system voltage is 9 - 16 volts.
^ The vehicle speed must be greater than 16 km/h (10 mph).
^ The transmission is NOT in Park/Neutral.
^ The engine is running.
^ The front axle is engaged.

Conditions for Setting the DTC
The system logs the DTC if the front propshaft input indicates a speed of less than 16 RPM for 30 seconds.

Action Taken When the DTC Sets
^ All Shifts to AUTO 4WD mode are disabled. If the current mode is AUTO 4WD, the system does not allow any further adaptive events, such as correcting wheel slip.
^ The SERVICE AWD indicator remains illuminated for the remainder of the current ignition cycle.

Conditions for Clearing the DTC
^ The transfer case shift control module clears the DTC when the condition for setting the DTC no longer exists.
^ A history DTC clears after 100 consecutive ignition cycles without a fault present.
^ History DTCs can be cleared using a scan tool.

Test Description








These numbers correspond to the step numbers on the diagnostic table.
2. This step tests to determine if the malfunction is intermittent.
3. This step tests the internal resistance of the propshaft speed sensor.
4. This step tests to determine if the propshaft speed sensor can generate a sufficient amount of AC voltage.
5. This step tests the front speed sensor low circuit for a short to ground, a high resistance, or an open.
6. This step tests the front speed sensor high circuit for a short to ground, a high resistance, or an open.
7. This step tests the front speed sensor low circuit for a short to voltage.
8. This step tests the front speed sensor high circuit for a short to voltage.
9. This step tests the front speed sensor low circuit for a short to the front speed sensor high circuit.