Front Control Module (FCM)

C1403-TRANSFER CASE RANGE POSITION SENSOR PERFORMANCE





For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.

- When Monitored:
With the ignition on. Battery voltage between 9.0 and 16.0 volts. No Range Position Sensor low or high voltage conditions present.

- Set Condition:
During a blocked shift attempt, the motor current indicates motor movement, but the sensor value change is less than a specified value.





1. DTC IS ACTIVE
1. Ignition on, engine not running.

NOTE: Repair any system undervoltage or overvoltage DTCs that are set in this module before proceeding.

2. With the scan tool, read the DTCs in the FCM.

Is the DTC status Active at this time?

Yes

- Go To 2

No

- Go To 11

2. (T103) 5 VOLT SUPPLY CIRCUIT VOLTAGE




1. Turn the ignition off to the lock position.
2. Disconnect the Shift Motor/Mode Sensor harness connector.
3. Ignition on, engine not running.
4. Measure the voltage of the (T103) Drivetrain 5-volt Supply circuit.

Select the correct displayed voltage reading:

Voltage greater than 5.5 volts.

- Repair the (T103) Drivetrain 5-volt Supply circuit for a short to voltage.
- Perform the TRANSFER CASE VERIFICATION TEST. Transfer Case Verification Test

Voltage between 4.5 and 5.5 volts.

- Go To 5

Voltage less than 4.5 volts.

- Go To 3

3. (T103) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT HIGH RESISTANCE




1. Turn the ignition off to the lock position.
2. Disconnect the FCM C1 harness connector.
3. Measure the resistance of the (T103) Drivetrain 5-volt Supply circuit between the FCM C1 harness connector and the Shift Motor/Mode Sensor harness connector.

Is the resistance above 5.0 Ohms?

Yes

- Repair the high resistance in the (T103) Drivetrain 5-volt Supply circuit.
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test

No

- Go To 4

4. (T103) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND




1. Measure the resistance between ground and the (T103) 5-volt Supply circuit.

Is the resistance below 5.0 Ohms?

Yes

- Repair the (T103) Drivetrain 5-volt Supply circuit for a short to ground.
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test

No

- Replace the Front Control Module (FCM).
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test

5. (D201) MODE SENSOR SIGNAL CIRCUIT HIGH RESISTANCE




1. Turn the ignition off to the lock position.
2. Disconnect the FCM C1 harness connector.
3. Measure the resistance of the (D201) Mode Sensor Signal circuit between the FCM C1 harness connector and the Shift Motor/Mode Sensor harness connector.

Is the resistance above 5.0 Ohms?

Yes

- Repair the high resistance in the (D201) Mode Sensor Signal circuit.
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test

No

- Go To 6

6. (D201) MODE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND




1. Measure the resistance between ground and the (D201) Mode Sensor Signal circuit.

Is the resistance below 5.0 Ohms?

Yes

- Repair the (D201) Mode Sensor Signal circuit for a short to ground.
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test

No

- Go To 7

7. (D201) MODE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE




1. Ignition on, engine not running.
2. Measure the voltage between ground and the (D201) Mode Sensor Signal circuit.

Is there any voltage present?

Yes

- Repair the (D201) Mode Sensor Signal circuit for a short to voltage.
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test

No

- Go To 8

8. (G180) FRONT CONTROL MODULE (FCM) SENSOR RETURN CIRCUIT HIGH RESISTANCE




1. Turn the ignition off to the lock position.
2. Measure the resistance between ground and the (G180) FCM Sensor Return circuit.

Is the resistance below 5.0 Ohms?

Yes

- Go To 9

No

- Repair the high resistance in the (G180) FCM Sensor Return circuit.
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test

9. (T103) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT FOR VOLTAGE




1. Turn the ignition off to the lock position.
2. Connect a jumper wire between the (D201) Mode Sensor Signal circuit and the (T103) 5 Volt Supply circuit.
3. Ignition on, engine not running.
4. With the scan tool under Data Display, read the T-Case Position Sensor voltage.
5. The displayed voltage should be approximately 5 volts with the jumper wire in place.

Does the voltage read 5.0 (± 0.02 volts)?

Yes

- Go To 10

No

- Replace the Front Control Module (FCM).
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test

10. (G180) FRONT CONTROL MODULE (FCM) SENSOR RETURN CIRCUIT FOR GROUND




1. Turn the ignition off to the lock position.
2. Connect a jumper wire between the (D201) Mode Sensor Signal circuit and the (G180) FCM Sensor Return circuit.
3. Ignition on, engine not running.
4. With the scan tool under Data Display, read the Transfer Case Position Sensor voltage.
5. The displayed voltage should be approximately 0 volts with the jumper wire in place.

Does the voltage read 0.0 (± 0.02 volts)?

Yes

- Replace the Transfer Case Motor.
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test

No

- Replace the Front Control Module (FCM).
- Perform the TRANSFER CASE VERIFICATION TEST Transfer Case Verification Test
11. INTERMITTENT WIRING 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. While monitoring the scan tool data relative to this circuit, wiggle test the wiring harness and connectors.
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 Transfer Case Verification Test

No

- Test complete.