C1408

C1408-TRANSFER CASE BRAKE CONTROL CIRCUIT HIGH







- When Monitored:
With the ignition on and no undervoltage or overvoltage condition present.

- Set Condition:
The Final Drive Control Module (FDCM) detects that the Transfer Case Motor Lock Circuit diagnostic input is high when the output is on.





1. DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, record and erase DTCs.
3. Test drive the vehicle.
4. Ignition on, engine not running.
5. With the scan tool, read DTCs.

Does the DTC reset?

Yes

- Go To 2

No

- Go To 7

2. (T301) SWITCHED BATTERY SOLENOID SUPPLY CIRCUIT OPEN




1. Turn the ignition off to the lock position
2. Disconnect the Transfer Case Motor harness connector.
3. Disconnect the FDCM C1 harness connector.
4. Measure the resistance of the (T301) Switched Battery Solenoid Supply circuit between the Transfer Case Motor harness connector and the FDCM C1 harness connector.

Is the resistance above 5.0 Ohms?

Yes

- Repair the (T301) Switched Battery Solenoid Supply circuit for an open.
- Perform TRANSFER CASE VERIFICATION TEST. Transfer Case Verification Test.

No

- Go To 3

3. (T317) TRANSFER CASE MOTOR LOCK SIGNAL CIRCUIT OPEN




1. Measure the resistance of the (T317) Transfer Case Motor Lock Signal circuit between the Transfer Case Motor harness connector and the FDCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Repair the (T317) Transfer Case Motor Lock Signal circuit for an open.
- Perform TRANSFER CASE VERIFICATION TEST. Transfer Case Verification Test.

No

- Go To 4

4. (T301) SWITCHED BATTERY SOLENOID SUPPLY CIRCUIT SHORTED TO VOLTAGE




1. Ignition on, engine not running.
2. Measure the voltage of the (T301) Switched Battery Solenoid Supply circuit in the Transfer Case Motor harness connector.

Is any voltage present?

Yes

- Repair the (T301) Switched Battery Solenoid Supply circuit for a short to voltage.
- Perform TRANSFER CASE VERIFICATION TEST. Transfer Case Verification Test.

No

- Go To 5

5. TRANSFER CASE MOTOR




1. Turn the ignition off to the lock position
2. Reconnect the Transfer Case Motor harness connector.
3. Measure the resistance of the (T317) Transfer Case Motor Lock Signal circuit and the (T301) Switched Battery Solenoid Supply in the FDCM C1 harness connector.

Is the resistance above 10.0 Ohms?

Yes

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

No
Go To 6

6. FINAL DRIVE CONTROL MODULE (FDCM)
1. Reconnect the FDCM C1 harness connector.
2. Ignition on, engine not running.
3. With the scan tool, erase DTCs.
4. With the scan tool, read DTCs.

Does the DTC P1408-Transfer Case Brake Control Circuit High set?

Yes

- Replace the Final Drive Control Module (FDCM).
- Perform the TRANSFER CASE VERIFICATION TEST. Transfer Case Verification Test.

No

- Go To 7

7. 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. Transfer Case Verification Test.

No

- Test complete.