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Dan
Dan, ASE Certified Technician
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2009 Jeep Grand Cherokee code c1438..does that mean transfer

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2009 Jeep Grand Cherokee code c1438..does that mean transfer case needs to be rebuilt or replaced

Hello my name is***** am an ASE Master Technician and I am glad to help you out with your question.

Most likely the transfer case needs to be replaced, but this also could be an electrical problem. This code will need to be diagnosed.

C1438-TRANSFER CASE DIFFERENTIAL CLUTCH WORN

Circuit Schematic

Fig 1: Mode Select Circuit & Drivetrain 5 Volt Supply Circuit Schematic

Courtesy of CHRYSLER LLCView Full-Screen

Additional Wiring

For complete wiring diagrams, refer to SYSTEM WIRING DIAGRAMS .

Monitor Conditions

  • 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 Conditions

  • Set Condition:

    The Final Drive Control Module (FDCM) is unable to fully lock the T-Case (in Either High or Low) because the T-Case clutch is worn.

Possible Causes

Possible Causes

(K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE

(T313) MODE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

(K594) DRIVETRAIN SENSOR RETURN CIRCUIT OPEN OR HIGH RESISTANCE

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.

    1. Ignition on, engine running.
    2. With the scan tool, clear stored DTCs.
    3. Test drive the vehicle.
    4. During the test drive, move the Transfer Case Selector Switch to each position several times in accordance with the Service Information.
    5. With the scan tool, read DTCs.

      Does this DTC reset?

      Yes

      • Go to step 2

      No

      • Go to step 7
  2. TRANSFER CASE POSITION SENSOR VOLTAGE

    Fig 2: Checking Transfer Case Motor

    Courtesy of CHRYSLER LLCView Full-Screen
    1. Turn the ignition off to the lock position.
    2. Disconnect the Transfer Case Motor harness connector.
    3. Connect a jumper wire between the (T313) Mode Sensor Signal circuit and the (K594) Drivetrain Sensor Return circuit.
    4. Ignition on, engine running.
    5. With the scan tool, read the T-Case Position Sensor voltage.
    6. The displayed voltage should be approximately 0.0 volts with the jumper wire in place.

      Does the voltage display as described?

      Yes

      • Replace the Transfer Case Clutch in accordance with the Service Information.
      • Perform the TRANSFER CASE VERIFICATION. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure

      No

      • Go to step 3
  3. TRANSFER CASE POSITION SENSOR VOLTAGE

    Fig 3: Checking Transfer Case Position Sensor Voltage

    Courtesy of CHRYSLER LLCView Full-Screen
    1. Turn the ignition off to the lock position.
    2. Connect a jumper wire between the (T313) Mode Sensor Signal circuit and the (K504) Drivetrain 5 Volt Supply circuit in the Transfer Case Motor harness connector.
    3. Ignition on, engine running.
    4. With the scan tool, monitor the T-Case Position Sensor voltage in the FDCM.

      Is the voltage between 4.8 volts and 5.2 volts?

      Yes

      • Replace or Repair the Transfer Case Clutch in accordance with the Service Information.
      • Perform the TRANSFER CASE VERIFICATION. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure

      No

      • Go to step 4
  4. (K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT HIGH RESISTANCE

    Fig 4: Checking Drivetrain 5 Volt Supply Circuit High Resistance

    Courtesy of CHRYSLER LLCView Full-Screen
    1. Turn the ignition off to the lock position
    2. Disconnect the Final Drive Control Module C2 harness connector.
    3. 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. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .

      No

      • Go to step 5
  5. (T313) MODE SENSOR SIGNAL CIRCUIT HIGH RESISTANCE

    Fig 5: Checking Mode Sensor Signal Circuit High Resistance

    Courtesy of CHRYSLER LLCView Full-Screen
    1. Turn the ignition off to the lock position
    2. Disconnect the Final Drive Control Module C2 harness connector.
    3. 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. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .

      No

      • Go to step 6
  6. (K594) DRIVETRAIN SENSOR RETURN CIRCUIT HIGH RESISTANCE

    Fig 6: Checking Drivetrain Sensor Return Circuit High Resistance

    Courtesy of CHRYSLER LLCView Full-Screen
    1. 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

      • Replace the Final Drive Control Module (FDCM) in accordance with the Service Information.
      • Perform the TRANSFER CASE VERIFICATION. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .

      No

      • Repair the high resistance in the (K594) Drivetrain Sensor Return circuit.
      • Perform the TRANSFER CASE VERIFICATION. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  7. INTERMITTENT WIRING AND CONNECTORS
    1. The conditions necessary to set this DTC are not present at this time.
    2. Using the SYSTEM WIRING DIAGRAMS as a guide, inspect the wiring and connectors.
    3. While monitoring the scan tool data relative to this circuit, wiggle test the wiring and connectors.
    4. 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. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .

      No

      • Test complete.

Please reply to this if you need more help and we can continue this conversation at no extra charge. This does not have to be my only answer. If you are satisfied with my service, please rate at the top of the screen. Rating does not close out your question. Remember, sometimes it is difficult to completely diagnose your vehicle without being there, but I will try to give you the best answer I can. Hoping to be giving you 5 star service.

Thanks,

Dan

Hello again Dan here,

I am contacting you because the post has not been closed or rated.

This question is coming up on 7 days which means it will time out and close.

You have already paid to get this question answered, but you have not rated.

Let me help some more. Is there anything else I can help you with?

If I did not give you 5 star service, please let me know what I missed.

Thanks

Dan and 2 other Car Specialists are ready to help you

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