C1438

C1438-TRANSFER CASE DIFFERENTIAL CLUTCH WORN





- When Monitored:
The ignition on, engine running. No Under/Overvoltage, and/or encoder error DTCs present. When shifted into 4-Low or in 4-high.
- Set Condition:
The Final Drive Control Module is unable to fully lock the T-Case (in Either High or Low) because the T-Case clutch is worn.

Possible Causes
(K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT OPEN
(T313) MODE SENSOR SIGNAL CIRCUIT OPEN
(K594) DRIVETRAIN SENSOR RETURN CIRCUIT OPEN
TRANSFER CASE CLUTCH
FINAL DRIVE CONTROL MODULE (FDCM)

Diagnostic Test
1. DTC IS ACTIVE

NOTE: Diagnose and repair any system voltage or Transfer Case related DTCs in the FDCM before continuing with this test.

Ignition on, engine running.
With the scan tool, clear stored DTCs in the Final Drive Control Module.
Test drive the vehicle.
During the test drive, move the Transfer Case Selector Switch to each position several times.
With the scan tool, read DTCs in the Final Drive Control Module.
Does this DTC reset?
Yes >>Go to 3
No >>Go to 5





2. (K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT HIGH RESISTANCE
Turn the ignition off to the lock position
Disconnect the Final Drive Control Module C2 harness connector.
Measure the resistance of the (K504) Drivetrain 5 Volt Supply circuit between the Transfer Case Motor harness connector and the Final Drive Control Module C2 harness connector.
Is the resistance above 5.0 ohms?
Yes >>Repair the high resistance in the (K504) Drivetrain 5 Volt Supply circuit.
Perform the TRANSFER CASE VERIFICATION TEST-VER 1 Transfer Case Verification Test
No >>Go to 6





3. (T313) MODE SENSOR SIGNAL CIRCUIT HIGH RESISTANCE
Turn the ignition off to the lock position
Disconnect the Final Drive Control Module C2 harness connector.
Measure the resistance of the (T313) Mode Sensor Signal circuit between the Transfer Case Motor harness connector and the Final Drive Control Module C2 harness connector.
Is the resistance above 5.0 ohms?
Yes >>Repair the high resistance in the (T313) Mode Sensor Signal circuit.
Perform the TRANSFER CASE VERIFICATION TEST-VER 1 Transfer Case Verification Test
No >>Go to 9





4. (K594) DRIVETRAIN SENSOR RETURN CIRCUIT HIGH RESISTANCE
Measure the resistance of the (K594) Drivetrain Sensor Return circuit between the Transfer Case Motor harness connector and the Final Drive Control Module C2 harness connector.
Is the resistance below 5.0 ohms?
Yes >>Go to 5
No >>Repair the high resistance in the (K594) Drivetrain Sensor Return circuit. Perform the TRANSFER CASE VERIFICATION TEST-VER 1 Transfer Case Verification Test

5. FINAL DRIVE CONTROL MODULE
Turn the ignition off to the lock position.
Replace the Transfer Case Selector Switch.
Ignition on, engine not running.
With the scan tool, clear stored DTCs in the Final Drive Control Module.
Test drive the vehicle.
During the test drive, move the Transfer Case Selector Switch to each position several times.
With the scan tool, read DTCs in the Final Drive Control Module.
Does this DTC reset?
Yes >>Replace the Final Drive Control Module. Perform the TRANSFER CASE VERIFICATION TEST-VER 1 Transfer Case Verification Test
No >>Test Complete. Perform the TRANSFER CASE VERIFICATION TEST-VER 1 Transfer Case Verification Test

6. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
While monitoring the scan tool data relative to this circuit, wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Were any problems found?
Yes >>Repair as necessary. Perform the TRANSFER CASE VERIFICATION TEST-VER 1 Transfer Case Verification Test
No >>Test complete.