C140B

C140B- TRANSFER CASE MOTOR CONTROL CIRCUIT LOW





For a complete wiring diagram, refer to Wiring Diagram Information.
^ When Monitored:
Ignition on. Battery voltage between 9 and 16 volts.
^ Set Condition:
FCM detects low voltage on the Transfer Case Motor Control Circuit for 0.5 seconds.

Possible Causes
- INTERMITTENT CONDITION
- (T101) SHIFT MOTOR + (POS) CIRCUIT OPEN
- (T102) SHIFT MOTOR - (NEG) CIRCUIT OPEN
- (T101) SHIFT MOTOR + (POS) CIRCUIT SHORTED TO GROUND
- (T102) SHIFT MOTOR - (NEG) CIRCUIT SHORTED TO GROUND
- (T101) SHIFT MOTOR + (POS) CIRCUIT SHORTED TO (T102) SHIFT MOTOR ? (NEG) CIRCUIT
- SHIFT MOTOR/MODE SENSOR ASSEMBLY
- FRONT CONTROL MODULE
- POWER DISTRIBUTION MODULE

Diagnostic Test
1. SHIFT MOTOR DTC IS ACTIVE
Ignition on, engine not running.
With the scan tool, Clear DTCs.
Move the Shift control to each position, while monitoring the Data Display on the scan tool.
Does the DTC reset?
Yes >>Go to 2
No >>Go to 10

2. SHIFT MOTOR CIRCUIT RESISTANCE AT FCM CONNECTOR





Turn the ignition off.
Remove the Front Control Module (FCM) from the Power Distribution Module (PDM).
Measure the resistance between the Shift Motor (+) circuit and the Shift Motor (-) circuit in the FCM connector of the PDM.
Is the resistance between 40 and 100 ohms?
Yes >>Go to 9
No >>Go to 3

3. SHIFT MOTOR CIRCUIT RESISTANCE AT PDM CONNECTOR





Disconnect the Power Distribution Module (PDM) C2 connector.
Measure the resistance between the Shift Motor (+) circuit and the Shift Motor (-) circuit at the PDM C2 connector.
Is the resistance between 40 and 100 ohms?
Yes >>Replace the Power Distribution Module (PDM).
Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Transfer Case Verification Test
No >>Go to 4

4. (T101) SHIFT MOTOR + (POS) CIRCUIT OPEN





Disconnect the Shift Motor/Mode Sensor Assembly connector.
Measure the resistance of the (T101) Shift Motor + (pos) circuit from the Shift Motor/Mode Sensor Assembly connector to the Power Distribution Module C2 connector.
Is the resistance above 5.0 ohms?
Yes >>Repair the (T101) Shift Motor + (pos) circuit for an open.
Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Transfer Case Verification Test
No >>Go to 5

5. (T102) SHIFT MOTOR-(NEG) CIRCUIT OPEN





Measure the resistance of the (T102) Shift Motor-(neg) circuit from the Shift Motor/Mode Sensor Assembly connector to the Power Distribution Module C2 connector.
Is the resistance above 5.0 ohms?
Yes >>Repair the (T102) Shift Motor-(neg) circuit for an open.
Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Transfer Case Verification Test
No >>Go to 6

6. (T101) SHIFT MOTOR + (POS) CIRCUIT SHORTED TO GROUND





Measure the resistance between ground and the (T101) Shift Motor + (pos) circuit at the Shift Motor/Mode Sensor Assembly connector.
Is the resistance below 5.0 ohms?
Yes >>Repair the (T101) Shift Motor + (pos) circuit for a short to ground.
Perform the TRANSFER CASE VERIFICATION TEST VER 1. Transfer Case Verification Test
No >>Go to 7

7. (T102) SHIFT MOTOR-(NEG) CIRCUIT SHORTED TO GROUND





Measure the resistance between ground and the (T102) Shift Motor- (neg) circuit at the Shift Motor/Mode Sensor Assembly connector.
Is the resistance below 5.0 ohms?
Yes >>Repair the (T102) Shift Motor-(neg) circuit for a short to ground.
Perform the TRANSFER CASE VERIFICATION TEST VER 1. Transfer Case Verification Test
No >>Go to 8

8. (T101) SHIFT MOTOR + (POS) CIRCUIT SHORTED TO (T102) SHIFT MOTOR-(NEG) CIRCUIT





Measure the resistance between (T101) Shift Motor + (pos) circuit and the (T102) Shift Motor-(neg) circuit at the Shift Motor/Mode Sensor Assembly connector.
Is the resistance below 5.0 ohms?
Yes >>Repair the (T101) Shift Motor + (pos) circuit for a short to the (T102) Shift Motor-(neg) circuit.
Perform the TRANSFER CASE VERIFICATION TEST VER 1. Transfer Case Verification Test
No >>Replace the Shift Motor/Mode Sensor assembly in accordance with the Service Information.
Perform the TRANSFER CASE VERIFICATION TEST VER 1. Transfer Case Verification Test

9. FRONT CONTROL MODULE
Using the wiring diagram/schematic as a guide, inspect all wiring and connectors that pertain to this circuit.
Were any problems found?
Yes >>Repair as necessary.
Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Transfer Case Verification Test
No >>Replace the Front Control Module in accordance with the Service Information.
Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Transfer Case Verification Test

10. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
While monitoring the scan tool data relative to this circuit, wiggle test the wiring and connectors.
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 TEST-VER 1. Transfer Case Verification Test
No >>Test complete.