Circuit Description
The transfer case shift control module controls the transfer case lock solenoid. The lock is energized, locking action released, grounding the lock control circuit during gear shifts and in AUTO 4WD mode of operation. When power or ground is removed from the lock solenoid, locking action applied, the transfer case motor is prevented from moving. In this manner, the system is capable of providing a 4H and 4L lock-up without the need of additional vehicle power to hold the transfer case in these positions.
This DTC detects an open lock control circuit or an open lock feed.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | System voltage is 9-16 volts. |
Conditions for Setting the DTC
| • | The system tries to turn the lock solenoid off by opening the ground circuit. |
| • | If the module is unable to de-energize the solenoid, the system will not attempt to de-energize the solenoid again during that ignition cycle. |
| • | Transfer case lock output reads back as a low voltage when a high voltage is expected. |
Action Taken When the DTC Sets
| • | The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle. |
| • | All shifting is disabled. |
Conditions for Clearing the DTC
| • | The transfer case shift control module clears the DTC if 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
The numbers below refer to the step numbers on the diagnostic table.
-
This step measures for proper voltage on the battery positive voltage circuit.
-
This step measures the resistance through the lock control solenoid.
-
This step measures for a short to ground in the transfer case lock solenoid.
-
This step tests the transfer case lock solenoid circuit for a short to ground.
-
This step tests the transfer case lock solenoid circuit for an open.
-
This step repairs the battery positive voltage circuit for an open.
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 - Transfer Case? | -- | Go to Step 2 | |
Does the test lamp illuminate? | -- | Go to Step 3 | Go to Step 7 | |
Using a DMM, measure the resistance across the encoder motor lock control. Is the resistance reading within the specified value? | 20-80 ohms | Go to Step 4 | Go to Step 8 | |
Using a DMM at the transfer case side of the 4 pin connector, measure the transfer case lock solenoid circuit for a short to ground. Refer to Testing for Short to Ground in Wiring Systems. Did you find and correct the condition? | - | Go to Step 8 | Go to Step 5 | |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 | |
Test the transfer case lock solenoid circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | |
Check the battery positive voltage and lock solenoid control circuits for an open or high resistance. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | |
8 | Replace the motor encoder. Refer to Transfer Case Motor/Encoder Replacement . Did you complete the repair? | -- | Go to Step 10 | -- |
9 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Did you complete the repair? | -- | Go to Step 10 | -- |
10 |
Does the DTC set? | -- | Go to Step 2 | System OK |
