DTC C0306. HUMMER H2 2005

For 1990-2009 cars only

Makes 🢒 HUMMER 🢒 2005 🢒 H2 🢒 Driveline/Axle 🢒 Transfer Case - BW 4484 🢒 DTC C0306

Circuit Description

The transfer case motor is a bi-directional, permanent magnet, D.C. motor. When energized, through motor control A or motor control B, the ground is provided by the opposing motor control circuit and then grounded through the transfer case shift control module ground circuit, the motor, through a series of gears, rotates a shaft which moves the mode and range forks to shift the transfer case between the following ranges:

•

4HI

•

4HI Lock

•

4LO Lock

•

Neutral

This DTC detects an open, short to voltage, or short to ground in the motor control A or motor control B circuits, or an open, or short to ground inside the motor.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0306 Motor A or B Circuit Malfunction

Conditions for Running the DTC

•	The ignition is ON.

•	The system voltage is 9-18 volts.

Conditions for Setting the DTC

•	The system will test the motor circuits by checking for unwanted voltage.

•	Then, the system supplies voltage on each of the motor circuits and reads the voltage back on the other circuit.

•	If the system detects a problem with the circuits, the DTC is logged. The transfer case shift control module senses a low voltage return in the motor control A or motor control B circuits when a high voltage is expected.

•	The fault must remain current for 1.2 seconds to set the DTC.

Action Taken When the DTC Sets

•	All shifting will be disabled.

•	The SERVICE 4WD indicator will remain 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 below refer to the step numbers on the diagnostic table.

This step tests motor A driver high for proper operation.

This step tests motor B driver high for proper operation.

This step tests motor A driver low for proper operation.

This step tests motor B driver low for proper operation.

This step tests motor control A and motor control B circuits for being shorted together.

This step tests motor control A for a short to ground, short to voltage, open, or high resistance.

This step tests motor control B for a short to ground, short to voltage, open, or high resistance.

Step	Action	Value(s)	Yes	No
Schematic Reference: Transfer Case Control Schematics Connector End View Reference: Transfer Case Control Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	--	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Engage the parking brake. Turn the ignition OFF and raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information. Disconnect the motor encoder connector at the transfer case. Turn the ignition ON. With a digital multimeter (DMM), measure voltage by probing the motor control A circuit and take the other lead to a good ground. With a scan tool, command motor A driver high ON. Does the DMM indicate battery voltage?	--	Go to Step 3	Go to Step 7
3	With a DMM, measure voltage by probing the motor control B circuit and take the other lead to a good ground. With a scan tool, command motor B driver high ON. Does the DMM indicate battery voltage?	--	Go to Step 4	Go to Step 8
4	Using a DMM with the audible tone on, measure for continuity by probing the motor control A circuit and take the other lead to ground. With a scan tool, command motor A driver low ON. Does the DMM make an audible tone indicating continuity?	--	Go to Step 5	Go to Step 7
5	Using a DMM with the audible tone on, measure for continuity by probing the motor control B circuit and take the other lead to ground. With a scan tool, command motor B driver low ON. Does the DMM make an audible tone indicating continuity?	--	Go to Step 6	Go to Step 8
6	With a DMM, check motor control A and motor control B circuits for being shorted together. Did you find and correct the condition?	--	Go to Step 11	Go to Step 9
7	With a DMM, check the motor control A circuit for a short to ground, short to voltage, open, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 11	Go to Step 10
8	With a DMM, check the motor control B circuit for a short to ground, short to voltage, open, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 11	Go to Step 10
9	Replace the encoder motor. Refer to Transfer Case Motor/Encoder Replacement . Did you complete the repair?	--	Go to Step 11	--
10	Replace the transfer case shift control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming. Did you complete the repair?	--	Go to Step 11	--
11	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Setting the DTC as specified in the supporting text. Does the DTC reset?	--	Go to Step 2	System OK