Scheme 1
COMPONENT DESCRIPTION
| Components | Function |
|---|---|
| Transfer control unit | Controls transfer control device, control valves and shifts between 2WD/4WD and 4H/4LO. |
| Transfer control device | Integrates actuator motor and actuator position switch. |
| 2-4WD shift solenoid valve | Controls oil pressure and allows shifting between 2WD and 4WD. |
| Clutch pressure solenoid valve | Controls oil pressure and distributes torque between front and rear tires. |
| Line pressure switch | Detects line pressure. |
| Clutch pressure switch | Detects clutch pressure. |
| Transfer fluid temperature sensor | Detects transfer fluid temperature. |
| Actuator motor | Moves shift rods when signaled by transfer control unit. |
| Actuator position switch | Detects actuator motor position. |
| Wait detection switch | Detects whether or not 4WD lock gear is locked. |
| 4LO switch | Detects if transfer case is in 4LO. |
| ATP switch | Detects if transfer case is in neutral. |
| 4WD shift switch | Allows driver to select from 2WD/4WD, 4H/4LO and AUTO. |
| 4WD warning lamp | Illuminates if malfunction is detected in 4WD system. Flashes (1 flash/2 seconds) if large difference in diameter of front and rear tires. Flashes (2 flashes/1 second) if high transfer fluid temperature is detected. |
| ATP warning lamp | Indicates that A/T parking mechanism does not operate when A/T selector lever is in P position because transfer case is in neutral. |
| 4WD shift indicator lamp | Displays driving range selected by 4WD shift switch. |
| 4LO indicator lamp | Displays 4LO range. |
| ABS actuator and electric unit (control unit) | Transmits vehicle speed signal via CAN communication to transfer control unit. |
| TCM | Transmits the following signal via CAN communication to transfer control unit. Output shaft revolution signal A/T position indicator signal (transmission range switch signal) |
| ECM | Transmits the following signals via CAN communication to transfer control unit. Engine speed signal Accelerator pedal position signal |
COMPONENT DESCRIPTION CHART
Scheme 2
ALL-MODE 4WD Transfer Basic Control
Scheme 3
Hydraulic Control Circuits
Scheme 4
Operation Procedure
- Connect CONSULT-III.
- With engine at idle, touch SELF-DIAG RESULTS. Display shows malfunction experienced since the last erasing operation.
Note. The details for TIME are as follows: 0: Error currently detected with transfer control unit. Except for 0: Error detected in the past and memorized with transfer control unit. Detects frequency of driving after DTC occurs (frequency of turning ignition switch ON/OFF).
Description
If the engine starts when there is a malfunction in the 4WD system, the 4WD warning lamp turns ON or flickers in the combination meter. When the system functions properly, the warning lamp turns ON when the ignition switch is turned to ON, and it turns OFF after engine starts. To locate the cause of a malfunction, start the self-diagnosis function. The 4WD warning lamp in the combination meter will indicate the malfunction area by flashing according to the self-diagnostic results. Refer to " DTC INDEX ".
- Connect CONSULT-III.
- Touch DATA MONITOR.
- Select from SELECT MONITOR ITEM, screen of data monitor mode is displayed. NOTE: When malfunction is detected, CONSULT-III performs REAL-TIME DIAGNOSIS. Also, any malfunction detected while in this mode will be displayed at real time.
- Connect CONSULT-III.
- Touch WORK SUPPORT.
- Select from CLUTCH/F RLS LIM ADJ, screen of data monitor mode is displayed.
Power supply to transfer control unit is abnormally low while driving.
The transfer control unit controls the transfer control device which controls shifts between AUTO, 4H and 4LO and between 2WD and 4WD. A DTC may set when any of the following occur
- Malfunction is detected in the memory (RAM) system of transfer control unit.
- Malfunction is detected in the memory (ROM) system of transfer control unit.
- Malfunction is detected in the memory (EEPROM) system of transfer control unit.
- AD converter system of transfer control unit is malfunctioning.
The transmission control module (TCM) transmits the output shaft revolution signal via CAN communication to Transfer control unit. DTC P1807 will set when a malfunction is detected in the output shaft revolution signal or an improper signal is input while driving.
The ABS actuator and electric unit (control unit) transmits a vehicle speed signal via CAN communication to the transfer control unit. DTC P1808 sets when a malfunction is detected in the vehicle speed signal that is output from the ABS actuator and electric unit (control unit) or an improper signal is input while driving.
The neutral-4LO switch detects that the transfer case is in neutral or 4LO range. DTC P1810 will set when an improper signal from the neutral-4LO switch is input due to an open or short circuit.
The 4WD shift switch allows the driver to select AUTO, 2WD or 4WD and 4H or 4LO. DTC P1813 will set if more than two switch inputs are simultaneously detected by the transfer control unit due to a short circuit in the 4WD shift switch.
The wait detection switch detects if the transfer case is in 4WD. DTC P1814 will set if an improper signal from the wait detection switch is input due to open or short circuit.
The transmission range switch transmits the A/T position indicator signal (transmission range switch signal) via CAN communication to the transfer control unit. DTC P1816 will set when the transmission range switch signal is malfunctioning or there is a communication error.
The actuator motor receives signals from the transfer control unit and controls shift rods which shift the transfer case. DTC P1817 will set when any of the following occur
- Motor does not operate properly due to open or short circuit in actuator motor.
- Malfunction is detected in the actuator motor. (When 4WD shift switch is operated and actuator motor does not operate)
- Malfunction is detected in transfer shift high relay or transfer shift low relay.
The actuator position switch detects the current actuator motor range. DTC P1818 will set if either of the following occur
- Improper signal from actuator position switch is input due to open or short circuit.
- Malfunction is detected in actuator position switch.
The transfer control device integrates the actuator motor and actuator position switch. DTC P1819 will set if either of the following conditions exist
- Malfunction occurs in transfer control device actuator circuit.
- Malfunction is detected in the transfer shut off relay.
The ECM transmits the engine speed signal via CAN communication to the transfer control unit. DTC P1820 will set when either of the following occur
- Malfunction is detected in engine speed signal that is output from the ECM.
- Improper signal is input while driving.
Proper voltage is not applied to the clutch pressure solenoid valve due to open or short circuit.
Proper voltage is not applied to the 2-4WD solenoid valve due to an open or short circuit.
Motor does not operate properly due to open or short circuit in transfer motor or transfer motor relay.
Signal voltage from the transfer fluid temperature sensor is abnormally high (Transfer fluid temperature is abnormally low) while driving.
Improper signal from the clutch pressure switch is input due to open or short circuit. Also, a malfunction may have occurred in clutch pressure switch or hydraulic circuit.
Improper signal from line pressure switch is input due to open or short circuit. Also, a malfunction may have occurred in the line pressure switch or hydraulic circuit.
Malfunction is detected in accelerator pedal position signal that is output from ECM through CAN communication. Also, the signal voltage from accelerator pedal position sensor may be abnormally high or low.
Malfunction is detected in ABS operation signal that is output from ABS actuator and electric unit (control unit) through CAN communication.
Malfunction is detected in the VDC operation signal that is output from ABS actuator and electric unit (control unit) through CAN communication.
Malfunction is detected in TCS operation signal that is output from ABS actuator and electric unit (control unit) through CAN communication.
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring. Each control unit communicate data but selectively reads required data only.
4WD shift indicator lamp and 4LO indicator lamp do not turn ON for approx. 1 second when turning ignition switch to ON.
4WD warning lamp does not turn ON when turning ignition switch to ON.
4WD shift indicator lamp or 4LO indicator lamp do not change when switching the 4WD shift switch.
ATP warning lamp does not turn ON when the transfer case is switched in or out of 4LO with the A/T selector lever in N position.
The 4WD shift indicator lamp keeps flashing.
The 4WD warning lamp flashes quickly while driving (2 times/second). The lamp continues to flash until the ignition switch is turned OFF.
The 4WD warning lamp flashes slowly while driving (1 time/2 seconds). The lamp continues to flash until the ignition switch is turned OFF.
This symptom occurs when the vehicle is accelerating in 4WD and the steering wheel is turned fully either direction. It may feel like a bump or being pushed from behind. A small amount of this bumping feeling is acceptable under certain road conditions. The transfer case may be adjusted using the CONSULT-III to compensate for this condition.
The ATP indicator is ON when the transfer case is not in neutral.
The vehicle can not be put into 4WD mode. (Possible hydraulic malfunction)
- Connect both battery cables. NOTE: Supply power using jumper cables if battery is discharged.
- Use the Intelligent Key or mechanical key to turn the ignition switch to the "ACC" position. At this time, the steering lock will be released.
- Disconnect both battery cables. The steering lock will remain released and the steering wheel can be rotated.
- Perform the necessary repair operation.
- When the repair work is completed, return the ignition switch to the "LOCK" position before connecting the battery cables. (At this time, the steering lock mechanism will engage.)
- Perform a self-diagnosis check of all control units using CONSULT-III.