C0305

DTC C0305

Test 1-2:

Test 3-12:

Circuit Description
The front propshaft speed sensor is a permanent magnet (PM) generator.The PM 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 the following functions:
^ Calculations
^ To monitor the difference between the front and rear propshaft speed
^ In the AUTO, or the Adapt mode of operation, to determine the amount of slip and the percent of torque to apply to the front axle

The module accesses this input when the vehicle is in AUTO mode, 4HI, and 4LO ranges. The propshaft RPM can be displayed with a scan tool.
This DTC detects an open, short to ground, short to voltage or faulty sensor.

Conditions for Running the DTC
^ The ignition is ON.
^ System voltage is 9-18 volts.
^ Vehicle speed exceeds 16 km/h (10 mph).

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 while all of the following are true:
^ Transmission NOT in Park/Neutral
^ Engine is running
^ Front axle is engaged
^ Rear propshaft speed exceeds 512 RPM
^ Vehicle speed on Class 2 Data bus exceeds 16 km/h (10 mph)

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 the slip.
^ The SERVICE 4WD indicator remains illuminated 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 is not currently present.
^ A history DTC will clear after 100 consecutive ignition cycles without a fault present.
^ History DTCs can be cleared using a scan tool.

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