Transfer Case - Electronic Shift Ford Explorer Sport Trac I

Transfer Case - Electronic Shift

The four-wheel drive electronic shift-on-the-fly feature electrically shifts the vehicle transfer case between 2WD, 4WD HIGH, and 4WD LOW. The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. The operator is informed which mode the system is in by two instrument cluster indicators, one for 4WD HIGH which appears as 4WD HIGH, and one for 4WD LOW, which appears as 4WD LOW. Shifts into 4WD HIGH can be made at any speed. When shifting into 4WD HIGH with the vehicle stationary, tooth blockage may occur preventing shift completion. When the vehicle is driven above 8 km/h (5 mph) the shift will complete. When shifting in or out of 4WD LOW, the four-wheel drive (4WD) control module requires that the vehicle speed be less than 5 km/h (3 mph), the brake pedal be applied, and the transmission be in NEUTRAL.

The gearmotor encoder assembly is mounted externally on the transfer case. It drives a rotary cam which moves the mode fork and range fork within the transfer case between the 4WD HIGH, 4WD LOW, and 2WD range positions.

The four-wheel drive (4WD) control module controls the shift motor encoder assembly that shifts between 4WD HIGH, 4WD LOW, and 2WD modes.

The 4WD Control Module accomplishes shifts by interpreting inputs from the following

1. Mode Select Switch (MSS)
2. Vehicle Speed Signal
3. Encoder Plate Position
4. Brake Pedal Switch
5. Digital Transmission Range (TR) Sensor
6. Ignition Switch
7. Gearmotor Encoder Assembly

Based on these inputs, the 4WD Control Module controls the shifts into 2WD, 4WD HIGH or 4WD LOW with the following outputs

1. Gearmotor (Clockwise)
2. Gearmotor (Counterclockwise)

Scheme 3

1. Visually inspect for the following obvious signs of mechanical and electrical damage.
2. If the concern remains after the inspection, connect the scan tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the scan tool menu. If the scan 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.
3. If the scan tool still does not communicate with the vehicle, refer to the scan tool manufacturer's manual.
4. Carry out the DATA LINK DIAGNOSTICS test. If the scan tool responds with: CKT914, CKT915 or CKT70 = ALL ECUS NO RESP/NOT EQUIP, refer to «MODULE COMMUNICATIONS NETWORK»(/ford/explorer-sport-trac/i-2000-2005/remont/communication-devices/#module-communications-network) article. NO RESP/NOT EQUIP for 4WD Control Module, go to «PINPOINT TEST B: NO COMMUNICATION WITH FOUR-WHEEL DRIVE (4WD) CONTROL MODULE»(/ford/explorer-sport-trac/i-2000-2005/remont/transfer-case/#four-wheel-drive-systems) . SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out the 4WD Control Module self-test.
5. If the DTCs retrieved are related to the concern, go to «4WD CONTROL MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX»(/ford/explorer-sport-trac/i-2000-2005/remont/transfer-case/#four-wheel-drive-systems) table to continue diagnostics.
6. If no DTCs related to the concern are retrieved, carry out the Electronic Shift Function Test. Refer to «PINPOINT TEST A: ELECTRONIC SHIFT FUNCTIONAL TEST»(/ford/explorer-sport-trac/i-2000-2005/remont/transfer-case/#four-wheel-drive-systems__pinpoint-test-a-electronic-shift-functional) .

4WD CONTROL MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX