DIAGNOSIS AND TESTING

Diagnostic Test

NOTE: If the SKIM, PCM or FCM was replaced, refer to the service information for proper programming procedures.

• Disconnect all jumper wires and reconnect all previously disconnected components and connectors.
• Ensure that all accessories are turned off.
• Ensure that the battery is fully charged.
• If the FDCM was replaced as part of the repair you must program the new FDCM using the scan tool.
• With the scan tool, record and erase all DTC(s) from the FDCM
• Start and run the engine for 2 minutes while operating all functions of the system that caused the original concern.
• Turn the ignition off, wait 5 seconds, then turn the ignition on. Using the scan tool, read DTC(s) from the FDCM.

• The repair is not complete. Refer to the related category for the DTC or symptom that is still present.

• The repair is complete.

C1417-FRONT DIFFERENTIAL CONTROL CIRCUIT LOW

For a complete wiring diagram Refer to Section 8W.

• When Monitored:

  The Solenoid is active, no solenoid supply circuit DTCs are present and battery voltage is normal.

• Set Condition:

  The FDCM detects the Front Differential Solenoid Control is shorted low.

Diagnostic Test

• Inspect the Front Differential Solenoid Jumper harness, repair/replace as necessary. If OK, replace the Front Differential Solenoid.
• Perform FDCM VERIFICATION TEST.

• Repair the short to ground in the Front Differential Solenoid Control circuit.
• Perform FDCM VERIFICATION TEST.

• Repair the short to ground in the (T301) Switched Battery Solenoid Supply circuit.
• Perform FDCM VERIFICATION TEST.

NOTE: Before continuing, check the FDCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST

• Replace and program the Final Drive Control Module in accordance with Service Information.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Test Complete.

C1418-FRONT DIFFERENTIAL CONTROL CIRCUIT HIGH

For a complete wiring diagram Refer to Section 8W.

• When Monitored:

  The Solenoid is active, no solenoid supply circuit DTCs are present and battery voltage is normal.

• Set Condition:

  The FDCM detects the Front Differential Solenoid Control is high.

Diagnostic Test

• Inspect the Front Differential Solenoid Jumper harness connector, repair/replace as necessary. If OK, replace the Front Differential Solenoid.
• Perform FDCM VERIFICATION TEST.

• Repair the short to voltage in the (T306) Front Differential Solenoid Control circuit.
• Perform FDCM VERIFICATION TEST.

• Repair the short between the (T306) Front Differential Solenoid Control circuit and the (T301) Switched Battery Solenoid Supply circuit.
• Perform FDCM VERIFICATION TEST

NOTE: Before continuing, check the FDCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST

• Replace and program the Final Drive Control Module in accordance with Service Information.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Test Complete.

C141A-FRONT DIFFERENTIAL CONTROL CIRCUIT “CURRENT” PERFORMANCE

For a complete wiring diagram Refer to Section 8W.

• When Monitored:

  The ignition on. No Solenoid DTCs present.

• Set Condition:

  The FDCM detects a current feedback when the solenoid is not active.

Diagnostic Test

NOTE: You must diagnose any Solenoid circuit (Low or High) DTCs first if set along with this DTC before continuing.

• Replace the FDCM in accordance with the Service Manual.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Test Complete.

C141B-FRONT DIFFERENTIAL CLUTCH PERFORMANCE

For a complete wiring diagram Refer to Section 8W.

• When Monitored:

  The ignition on. No Solenoid DTCs present.

• Set Condition:

  The solenoid duty cycle is greater than 95% and the wheel slippage is greater than 50%.

Diagnostic Test

NOTE: You must diagnose any Solenoid circuit (Low or High) DTCs first if set along with this DTC before continuing.

• Replace the Front Differential Solenoid.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Test Complete.

C141D-REAR DIFFERENTIAL CONTROL CIRCUIT LOW

For a complete wiring diagram Refer to Section 8W.

• When Monitored:

  The Solenoid is active, no solenoid supply circuit DTCs are present and battery voltage is normal.

• Set Condition:

  The FDCM detects the Rear Differential Solenoid Control is shorted low.

Diagnostic Test

• Inspect the Rear Differential Solenoid Jumper harness, repair/replace as necessary. If OK, replace the Rear Differential Solenoid.
• Perform FDCM VERIFICATION TEST.

• Repair the short to ground in the Rear Differential Solenoid Control circuit.
• Perform FDCM VERIFICATION TEST.

• Repair the short to ground in the (T301) Switched Battery Solenoid Supply circuit.
• Perform FDCM VERIFICATION TEST.

NOTE: Before continuing, check the FDCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST

• Replace and program the Final Drive Control Module in accordance with Service Information.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Test Complete.

C141E-REAR DIFFERENTIAL CONTROL CIRCUIT HIGH

For a complete wiring diagram Refer to Section 8W.

• When Monitored:

  The Solenoid is active, no solenoid supply circuit DTCs are present and battery voltage is normal.

• Set Condition:

  The FDCM detects the Rear Differential Solenoid Control is high.

Diagnostic Test

• Inspect the Rear Differential Solenoid Jumper harness connector, repair/replace as necessary. If OK, replace the Rear Differential Solenoid.
• Perform FDCM VERIFICATION TEST.

• Repair the short to voltage in the (T312) Rear Differential Solenoid Control circuit.
• Perform FDCM VERIFICATION TEST.

• Repair the short between the (T312) Rear Differential Solenoid Control circuit and the (T301) Switched Battery Solenoid Supply circuit.
• Perform FDCM VERIFICATION TEST

NOTE: Before continuing, check the FDCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST

• Replace and program the Final Drive Control Module in accordance with Service Information.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Test Complete.

C1420-REAR DIFFERENTIAL CONTROL CIRCUIT “CURRENT” PERFORMANCE

For a complete wiring diagram Refer to Section 8W.

• When Monitored:

  The ignition on. No Solenoid DTCs present.

• Set Condition:

  The FDCM detects a current feedback when the solenoid is not active.

Diagnostic Test

NOTE: You must diagnose any Solenoid circuit (Low or High) DTCs first if set along with this DTC before continuing.

• Replace the FDCM in accordance with the Service Manual.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Test Complete.

C1421-REAR DIFFERENTIAL CLUTCH PERFORMANCE

For a complete wiring diagram Refer to Section 8W.

• When Monitored:

  The ignition on. No Solenoid DTCs present.

• Set Condition:

  The solenoid duty cycle is greater than 95% and the wheel slippage is greater than 50%.

Diagnostic Test

NOTE: You must diagnose any Solenoid circuit (Low or High) DTCs first if set along with this DTC before continuing.

• Replace the Rear Differential Solenoid.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Test Complete.

C2109-DRIVETRAIN SUPPLY VOLTAGE CIRCUIT LOW

For a complete wiring diagram Refer to Section 8W.

• When Monitored:

  Ignition on.

• Set Condition:

  The FDCM recognizes the Switched Battery Solenoid Supply circuit voltage is too low.

Diagnostic Test

• Repair the open in the (T301) Switch Battery Solenoid Supply circuit.
• Perform FDCM VERIFICATION TEST.

• Repair the short to ground in the (T301) Switch Battery Solenoid Supply circuit.
• Perform FDCM VERIFICATION TEST.

• Inspect the Front Differential Solenoid jumper harness connector, repair/replace as necessary. If OK, replace the shorted Front Differential Solenoid in accordance with the Service Information.
• Perform FDCM VERIFICATION TEST.

• Inspect the Rear Differential Solenoid jumper harness connector, repair/replace as necessary. If OK, replace the shorted Rear Differential Solenoid in accordance with the Service Information.
• Perform FDCM VERIFICATION TEST.

• Replace the shorted Transfer Case Motor in accordance with the Service Information.
• Perform FDCM VERIFICATION TEST.

NOTE: Before continuing, check the FDCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST

• Replace and program the Final Drive Control Module in accordance with Service Information.
• Perform FDCM VERIFICATION TEST.

• Repair as necessary.
• Perform FDCM VERIFICATION TEST.

• Test Complete.