Scheme 1
Principles of Operation
The transfer case clutch is a torque distribution device that can be enabled and disabled from the instrument cluster message center through the four-wheel drive control module. It is non-repairable. The internal construction of the clutch consists of alternating plates that are connected to the front and rear outputs of the transfer case. The resistance to shear causes the plates to transmit torque at the needed ratio. The ratio that torque is transmitted is approximately 35% front and 65% rear.
Torque is transmitted from the input shaft through the collar to the rear output shaft assembly.
Torque also flows from the rear output shaft through the clutch pack assembly which is splined to the drive sprocket.
The drive gear is connected to the driven sprocket by the drive chain. Torque continues through the driven sprocket to the front output shaft flange. The transfer case clutch provides the connection between the gear ring and the sun gear shaft.
Four-Wheel Drive Systems - AWD
Refer to TRANSMISSION Wiring Diagrams for schematic and connector information.
Scheme 2
Scheme 3
- Verify the customer concern.
- Visually inspect for obvious signs of mechanical for electrical damage.
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
- If the concern is not visually evident, connect the diagnostic tool to the data link connector and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle: check that the program card is correctly installed. check the connections to the vehicle. check the ignition switch position.
- If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.
- Carry out the diagnostic data link test. If the diagnostic tool responds with: SCP+, SCP-, or UBP circuits fault; all ECUs no response/not equipped, refer to «MODULE COMMUNICATIONS NETWORK»(ref-193023) . NO RESP/NOT EQUIP for 4WD control module, GO to «PINPOINT TEST A»(ref-193007-S39865487092005092300000) . SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out the 4WD control module self-test.
- If the DTCs retrieved are related to the concern, go to the 4WD control module Diagnostic Trouble Code (DTC) Index to continue diagnostics.
Four-Wheel Drive Control Module Diagnostic Trouble Code Index
| DTC | Description | Source | Action |
|---|---|---|---|
| B1317 | Battery Voltage High | 4WD Control Module | Refer to BATTERY & CHARGING SYSTEM . |
| B1318 | Battery Voltage Low | 4WD Control Module | Refer to BATTERY & CHARGING SYSTEM . |
| B1342 | ECU Defective | 4WD Control Module | CLEAR the DTCs. REPEAT the 4x4 module. REPEAT the self test. If DTC B1342 is retrieved, INSTALL a new 4x4 module. REFER to FOUR-WHEEL DRIVE (4WD) CONTROL MODULE . CLEAR the DTCs. REPEAT the self test. |
| B2105 | Throttle Position (TP) Input Out of Range - Low | 4WD Control Module | REFER to SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE . |
| B2106 | Throttle Position (TP) Input Out of Range - High | 4WD Control Module | REFER to SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE |
| P1824 | 4WD Clutch Relay Circuit Failure | 4WD Control Module | Go To PINPOINT TEST B . |
| P1826 | Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Battery | 4WD Control Module | Go To PINPOINT TEST B . |
| P1827 | Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Ground | 4WD Control Module | Go To PINPOINT TEST B . |
| U1900 | CAN Communication BUS fault | 4WD Control Module | Refer to MODULE COMMUNICATIONS NETWORK . |
| U1950 | UBP Communication BUS Fault | 4WD Control Module | Refer to MODULE COMMUNICATIONS NETWORK . |
| U2023 | External Node Fault | 4WD Control Module | Refer to MODULE COMMUNICATIONS NETWORK . |
| U2306 | Invalid UBP Data From Instrument Cluster (Node 60) | 4WD Control Module | Refer to MODULE COMMUNICATIONS NETWORK . |
| U2226 | Invalid UBP Data From PCM (Node 10) | 4WD Control Module | Refer to MODULE COMMUNICATIONS NETWORK . |
| For All Other DTCs | 4WD Control Module | Refer to MODULE COMMUNICATIONS NETWORK . |
FOUR-WHEEL DRIVE CONTROL MODULE DIAGNOSTIC TROUBLE CODE INDEX
Normal Operation
The 4WD control module communicates with the diagnostic tool through the universal asynchronous receiver-transmitter (UART)-based protocol (UBP) communications network circuit 693 (OG). If the 4WD control module loses power it will not be able to communicate. Check power circuit 972 (BK/WH) and ground circuit 1203 (BK/LB) for open. If circuits prove out, refer to MODULE COMMUNICATIONS NETWORK for further diagnostics.
With the key in the ON position, the 4WD control module supplies power and ground to the transfer case clutch through circuit 779 (BR) and 976 (OG). If the transfer case clutch circuit is not active, the vehicle will not operate in AWD. Check circuit 779 (BR) for an open or short to ground. Check circuit 976 (OG) for an open. If both circuits prove out, check the transfer case clutch for an open in the clutch coil. If the transfer case clutch is operating correctly, the fault would be in the 4WD control module.