<H1>DTC C0306</H1><A name=ss1-841813><A href="#ss1-841813">
<H5>Circuit Description</A></H5>
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: </P>
<UL type=BULLET>
<LI>4HI
<LI>4HI Lock
<LI>4LO Lock
<LI>N </LI>[/list]
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.</P><A name=ss2-841813><A href="#ss2-841813">
<H5>Conditions for Running the DTC</A></H5>
<UL type=BULLET>
<LI>The ignition is ON.
<LI>System voltage is 9-18volts. </LI>[/list]<A name=ss3-841813><A
href="#ss3-841813">
<H5>Conditions for Setting the DTC</A></H5>
<UL type=BULLET>
<LI>The system will test the motor circuits by checking for unwanted voltage.
<LI>Then, the system supplies voltage on each of the motor circuits and reads
the voltage back on the other circuit.
<LI>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.
<LI>The fault must remain current for 1.2seconds to set the DTC.
</LI>[/list]<A name=ss4-841813><A href="#ss4-841813">
<H5>Action Taken When the DTC Sets</A></H5>
<UL type=BULLET>
<LI>All shifting will be disabled.
<LI>The SERVICE 4WD indicator will remain illuminated for the remainder of the
current ignition cycle. </LI>[/list]<A name=ss5-841813><A href="#ss5-841813">
<H5>Conditions for Clearing the DTC</A></H5>
<UL type=BULLET>
<LI>The transfer case shift control module will clear the DTC if the condition
for setting the DTC is not currently present.
<LI>A history DTC will clear after 100 consecutive ignition cycles without a
fault present.
<LI>History DTCs can be cleared using a scan tool. </LI>[/list]<A
name=ss6-841813><A href="#ss6-841813">
<H5>Test Description</A></H5>
The numbers below refer to the step numbers on the diagnostic table.</P>
- <A name=TD02>
<LI value=2>
Tests motorA driver high for proper operation.</P><A name=TD03>
<LI value=3>
Tests motorB driver high for proper operation.</P><A name=TD04>
<LI value=4>
Tests motorA driver low for proper operation.</P><A name=TD05>
<LI value=5>
Tests motorB driver low for proper operation.</P><A name=TD06>
<LI value=6>
Tests motor controlA and motor controlB circuits for being
shorted together.</P><A name=TD07>
<LI value=7>
Tests motor controlA for a short to ground, short to voltage, open, or
high resistance.</P><A name=TD08>
<LI value=8>
Tests motor controlB for a short to ground, short to voltage, open, or
high resistance.</P></LI>
<TABLE width="100%" border=1>
<TBODY>
<TR>
<TH vAlign=bottom align=middle>
Step</P></TH>
<TH vAlign=bottom align=middle>
Action</P></TH>
<TH vAlign=bottom align=middle>
Value(s)</P></TH>
<TH vAlign=bottom align=middle>
Yes</P></TH>
<TH vAlign=bottom align=middle>
No</P></TH></TR>
<TR>
<TD vAlign=bottom colSpan=5>
Schematic Reference: <A
href="/servlets/CellHandler?CellId=69955&RefDoc=841813&evc=sm">Tra nsfer
Case Control Schematics</A> </P>
Connector End View Reference: <A
href="/servlets/CellHandler?CellId=69957&RefDoc=841813&evc=sm">Tra nsfer
Case Control Connector End Views</A> </P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S01>
1</P></A></TD>
<TD vAlign=top align=left>
Did you perform the Diagnostic System Check - Transfer Case?</P></TD>
<TD vAlign=center align=middle>
--</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step2 </P></TD>
<TD vAlign=bottom align=middle>
Go to <A
href="/servlets/CellHandler?CellId=69959&RefDoc=841813&evc=sm">Dia gnostic
System Check - Transfer Case</A> </P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S02>
2 </P></A></TD>
<TD vAlign=top align=left>
- <LI type=1>Engage the parking brake.
<LI type=1>Turn the ignition OFF and raise the vehicle on a hoist.
<LI type=1>Disconnect the motor encoder connector at the transfer case.
<LI type=1>Turn the ignition ON.
<LI type=1>With a DMM, measure voltage by probing the motor controlA
circuit and take the other lead to a good ground.
<LI type=1>With a scan tool, command motorA driver high ON. </LI>
Does the DMM indicate battery voltage?</P></TD>
<TD vAlign=center align=middle>
--</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step3 </P></TD>
<TD vAlign=bottom align=middle>
Go to
Step7 </P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S03>
3</P></A></TD>
<TD vAlign=top align=left>
- <LI type=1>With a DMM, measure voltage by probing the motor controlB
circuit and take the other lead to a good ground.
<LI type=1>With a scan tool, command motorB driver high ON. </LI>
Does the DMM indicate battery voltage?</P></TD>
<TD vAlign=center align=middle>
--</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step4 </P></TD>
<TD vAlign=bottom align=middle>
Go to
Step8 </P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S04>
4 </P></A></TD>
<TD vAlign=top align=left>
- <LI type=1>With a DMM, measure voltage by probing the motor controlA
circuit and take the other lead to ground.
<LI type=1>With a scan tool, command motorA driver low ON. </LI>
Does the voltage on the DMM match the voltage indicated?</P></TD>
<TD vAlign=center align=middle>
0V</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step5 </P></TD>
<TD vAlign=bottom align=middle>
Go to
Step7 </P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S05>
5</P></A></TD>
<TD>
- <LI type=1>With a DMM, measure voltage by probing the motor controlB
circuit and use the other lead to probe one of the four encoder signal circuits.
<LI type=1>With a scan tool, command motorB driver low ON. </LI>
Does the DMM indicate voltage within the specified range?</P></TD>
<TD vAlign=center align=middle>
4.3-4.7V</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step6 </P></TD>
<TD vAlign=bottom align=middle>
Go to
Step8 </P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S06>
6 </P></A></TD>
<TD>
With a DMM, check motor controlA and motor controlB circuits for
being shorted together.</P>
Did you find and correct the condition?</P></TD>
<TD vAlign=center align=middle>
--</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step11 </P></TD>
<TD vAlign=bottom align=middle>
Go to
Step9 </P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S07>
7</P></A></TD>
<TD vAlign=top align=left>
With a DMM, check the motor controlA circuit for a short to ground,
short to voltage, open, or high resistance.</P>
Refer to <A
href="/servlets/CellHandler?CellId=62194&RefDoc=841813&evc=sm">Cir cuit
Testing</A> and <A
href="/servlets/CellHandler?CellId=61965&RefDoc=841813&evc=sm">Wir ing
Repairs</A> in Wiring Systems.</P>
Did you find and correct the condition?</P></TD>
<TD vAlign=center align=middle>
--</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step11 </P></TD>
<TD vAlign=bottom align=middle>
Go to
Step10 </P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S08>
8 </P></A></TD>
<TD vAlign=top align=left>
With a DMM, check the motor controlB circuit for a short to ground,
short to voltage, open, or high resistance.</P>
Refer to <A
href="/servlets/CellHandler?CellId=62194&RefDoc=841813&evc=sm">Cir cuit
Testing</A> and <A
href="/servlets/CellHandler?CellId=61965&RefDoc=841813&evc=sm">Wir ing
Repairs</A> in Wiring Systems.</P>
Did you find and correct the condition?</P></TD>
<TD vAlign=center align=middle>
--</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step11 </P></TD>
<TD vAlign=bottom align=middle>
Go to
Step10 </P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S09>
9</P></A></TD>
<TD vAlign=top align=left>
Replace the encoder motor. Refer to <A
href="/servlets/CellHandler?CellId=69993&RefDoc=841813&evc=sm">Tra nsfer
Case Motor/Encoder Replacement</A> .</P>
Did you complete the repair?</P></TD>
<TD vAlign=center align=middle>
--</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step11 </P></TD>
<TD vAlign=center align=middle>
--</P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S10>
10</P></A></TD>
<TD vAlign=top align=left>
Replace the transfer case shift control module. Refer to <A
href="/servlets/CellHandler?CellId=69989&RefDoc=841813&evc=sm">Tra nsfer
Case Shift Control Module Replacement</A> .</P>
Did you complete the repair?</P></TD>
<TD vAlign=center align=middle>
--</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step11 </P></TD>
<TD vAlign=center align=middle>
--</P></TD></TR>
<TR>
<TD vAlign=center align=middle><A name=S11>
11</P></A></TD>
<TD vAlign=top align=left>
- <LI type=1>Use the scan tool in order to clear the DTCs.
<LI type=1>Operate the vehicle within the Conditions for Setting the DTC as
specified in the supporting text. </LI>
Does the DTC reset?</P></TD>
<TD vAlign=center align=middle>
--</P></TD>
<TD vAlign=bottom align=middle>
Go to
Step2</P></TD>
<TD vAlign=center align=middle>
System OK</P></TD></TR></TBODY></TABLE>
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