Diagnostic Test

WARNING: This page is about a different car, the 2009 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.

DTC IS ACTIVE
NOTE: This DTC sets when the Final Drive Control Module (FDCM) detects excessive voltage fluctuation on the Mode Sensor Signal circuit. Perform a thorough inspection of all wiring and connectors between the sensor and the control module.
1. Ignition on, engine not running.
2. With the scan tool, read DTCs.
  Is the status Active for this DTC?
  
  Yes
  - Go to step 2
  No
  - Go to step 14
(T504) DRIVETRAIN 5-VOLT SUPPLY VOLTAGE ERRATIC

Fig 1: CHECKING DRIVETRAIN 5-VOLT SUPPLY VOLTAGE ERRATIC
Courtesy of CHRYSLER LLC

NOTE: This DTC sets when the Final Drive Control Module (FDCM) detects excessive voltage fluctuation on the Mode Sensor Signal circuit. Perform a thorough inspection of all wiring and connectors between the sensor and the control module.
1. Turn the ignition off to the lock position
2. Disconnect the Transfer Case Motor harness connector.
3. Ignition on, engine not running.
4. Measure the voltage of the (T504) Drivetrain 5-volt Supply circuit at the Transfer Case Motor harness connector.
  NOTE: Voltage should be approximately 5.0 volts and steady. Compare any slight fluctuations found to a known good circuit in order to verify voltmeter functionality.
  
  Is the voltage approximately 5.0 volts and steady?
  
  Yes
  - Go to step 6
  No
  - Go to step 3
(T504) DRIVETRAIN 5-VOLT SUPPLY CIRCUIT INTERMITTENT SHORT TO VOLTAGE

Fig 2: CHECKING DRIVETRAIN 5-VOLT SUPPLY CIRCUIT INTERMITTENT FOR SHORT TO VOLTAGE
Courtesy of CHRYSLER LLC
1. Turn the ignition off to the lock position
2. Disconnect the FDCM C1 harness connector.
3. Ignition on, engine not running.
4. Measure the voltage of the (T504) Drivetrain 5-volt Supply circuit at the Transfer Case Motor harness connector.
5. Monitor the voltmeter while performing a wiggle test on the wiring harness and connectors.
  Is any voltage detected on the circuit during the wiggle test?
  
  Yes
  - Repair the (T504) Drivetrain 5-volt Supply circuit for an intermittent short to voltage.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  - Go to step 4
(T504) DRIVETRAIN 5-VOLT SUPPLY CIRCUIT HIGH RESISTANCE

Fig 3: CHECKING DRIVETRAIN 5-VOLT SUPPLY FOR INTERMITTENT OPEN CIRCUIT HIGH RESISTANCE
Courtesy of CHRYSLER LLC
1. Measure the resistance of the (T504) Drivetrain 5-volt Supply circuit between the Transfer Case Motor harness connector and the Final Drive Control Module C1 harness connector.
2. Monitor the ohmmeter while performing a wiggle test on the wiring harness and connectors.
  Is the resistance ever above 5.0 Ohms during the wiggle test?
  
  Yes
  - Repair the (T504) Drivetrain 5-volt Supply circuit for an intermittent open circuit or high resistance.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  - Go to step 5
(T504) DRIVETRAIN 5-VOLT SUPPLY CIRCUIT INTERMITTENT SHORT TO GROUND

Fig 4: CHECKING DRIVETRAIN 5-VOLT SUPPLY CIRCUIT FOR INTERMITTENT SHORT TO GROUND
Courtesy of CHRYSLER LLC
1. Measure the resistance between ground and the (T504) Drivetrain 5-volt Supply circuit at the Transfer Case Motor harness connector.
2. Monitor the ohmmeter while performing a wiggle test on the wiring harness and connectors.
  Is the resistance ever below 5.0 Ohms during the wiggle test?
  
  Yes
  - Repair the (T504) Drivetrain 5-volt Supply circuit for an intermittent short to ground.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  - Replace the Final Drive Control Module in accordance with the Service Information.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
T-CASE POSITION SENSOR VOLTAGE

Fig 5: CHECKING T-CASE POSITION SENSOR VOLTAGE
Courtesy of CHRYSLER LLC
1. Turn the ignition off to the lock position
2. Reconnect the Final Drive Control Module C1 harness connector.
3. Connect a jumper wire between the (T313) Mode Sensor Signal circuit and the (K594) Drivetrain Sensor Return circuit in the Transfer Case Motor harness connector.
4. Ignition on, engine not running.
5. With the scan tool read the T-Case Position Sensor Voltage in the Final Drive Control Module while performing a wiggle test on the wiring and connectors between the sensor and the control module.
  NOTE: Voltage should be approximately 0.0 volts and steady.
  
  Is the T-Case Position Sensor Voltage approximately 0.0 volts and steady?
  
  Yes
  - Go to step 12
  No
  - Go to step 7
(T313) MODE SENSOR SIGNAL CIRCUIT INTERMITTENT SHORT TO VOLTAGE

Fig 6: CHECKING MODE SENSOR SIGNAL CIRCUIT FOR INTERMITTENT SHORT TO VOLTAGE
Courtesy of CHRYSLER LLC

NOTE: Remove the previously installed jumper wire.
1. Turn the ignition off to the lock position
2. Disconnect the Final Drive Control Module C1 harness connector.
3. Ignition on, engine not running.
4. Measure the voltage of the (T313) Mode Sensor Signal circuit at the Transfer Case Motor harness connector.
5. Monitor the voltmeter while performing a wiggle test on the wiring harness and connectors.
  Is any voltage detected on the circuit during the wiggle test?
  
  Yes
  - Repair the (T313) Mode Sensor Signal circuit for an intermittent short to voltage.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  - Go to step 8
(K594) DRIVETRAIN SENSOR RETURN CIRCUIT INTERMITTENT SHORT TO VOLTAGE

Fig 7: CHECKING DRIVETRAIN SENSOR RETURN CIRCUIT FOR INTERMITTENT SHORT TO VOLTAGE
Courtesy of CHRYSLER LLC
1. Measure the voltage of the (K594) Drivetrain Sensor Return circuit at the Transfer Case Motor harness connector.
2. Monitor the voltmeter while performing a wiggle test on the wiring harness and connectors.
  Is any voltage detected on the circuit during the wiggle test?
  
  Yes
  - Repair the (K594) Drivetrain Sensor Return circuit for an intermittent short to voltage.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  - Go to step 9
(T313) MODE SENSOR SIGNAL CIRCUIT HIGH RESISTANCE

Fig 8: CHECKING MODE SENSOR SIGNAL FOR INTERMITTENT OPEN CIRCUIT OR HIGH RESISTANCE
Courtesy of CHRYSLER LLC
1. Turn the ignition off to the lock position
2. 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.
3. Monitor the ohmmeter while performing a wiggle test on the wiring harness and connectors.
  Is the resistance ever above 5.0 Ohms during the wiggle test?
  
  Yes
  - Repair the (T313) Mode Sensor Signal circuit for an intermittent open circuit or high resistance.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  - Go to step 10
(K594) DRIVETRAIN SENSOR RETURN CIRCUIT HIGH RESISTANCE

Fig 9: CHECKING DRIVETRAIN SENSOR RETURN CIRCUIT FOR INTERMITTENT OPEN CIRCUIT OR HIGH RESISTANCE
Courtesy of CHRYSLER LLC
1. Measure the resistance of the (K594) Drivetrain Sensor Return circuit between the Transfer Case Motor harness connector and the Final Drive Control Module C1 harness connector.
2. Monitor the ohmmeter while performing a wiggle test on the wiring harness and connectors.
  Is the resistance ever above 5.0 Ohms during the wiggle test?
  
  Yes
  - Repair the (K594) Drivetrain Sensor Return circuit for an intermittent open circuit or high resistance.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  - Go to step 11
(T313) MODE SENSOR SIGNAL CIRCUIT INTERMITTENT SHORT TO GROUND

Fig 10: CHECKING MODE SENSOR SIGNAL CIRCUIT FOR INTERMITTENT SHORT TO GROUND
Courtesy of CHRYSLER LLC
1. Measure the resistance between ground and the (T313) Mode Sensor Signal circuit at the Transfer Case Motor harness connector.
2. Monitor the ohmmeter while performing a wiggle test on the wiring harness and connectors.
  Is the resistance ever below 5.0 Ohms during the wiggle test?
  
  Yes
  - Repair the (T313) Mode Sensor Signal circuit for an intermittent short to ground.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  - Go to step 12
TRANSFER CASE MOTOR
NOTE: This DTC sets when the Final Drive Control Module detects excessive voltage fluctuation on the Mode Sensor Signal circuit. Perform a thorough inspection of all wiring and connectors between the sensor and the control module.
1. Using the schematic as a guide, inspect the Final Drive Control Module power and ground circuits.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  
  Go to step 13
TRANSFER CASE MOTOR/ENCODER
1. Replace the Transfer Case Motor/ Encoder in accordance with the Service Information.
  Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
2. Test drive the vehicle.
3. With the scan tool, read the DTCs in the Final Drive Control Module.
  Does this DTC reset?
  
  Yes
  - Replace the FDCM in accordance with the Service Information.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  
  Test complete.
INTERMITTENT WIRING HARNESS AND CONNECTORS
1. The conditions necessary to set this DTC are not present at this time.
2. Using the wiring diagram/schematic as a guide, inspect the wiring harness and connectors.
3. Wiggle test the wiring harness and connectors while monitoring the scan tool data relative to this circuit.
4. Look for the data to change or for the DTC to reset during the wiggle test.
5. While monitoring the scan tool data relative to this circuit, move the selector switch to each position several times.
6. Look for the data to change other than as expected or for the DTC to reset.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the TRANSFER CASE VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Final Drive Control (FDCM) - Standard Procedure .
  No
  - Test complete.