Scheme 1
COMPONENT DESCRIPTION
| Components | Function |
|---|---|
| Transfer control unit | Controls transfer control device and controls shifts between 2WD/4WD and 4H/4LO. |
| Transfer control device | Integrates actuator motor and actuator position switch. |
| Actuator motor | Moves shift rods when signaled by transfer control unit. |
| Actuator position switch | Detects actuator motor position. |
| Wait detection switch | Detects if transfer case is in 4WD. |
| 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 and 4H/4LO. |
| 4WD warning lamp | Illuminates if malfunction is detected in 4WD system. Flashes (1 flash/2 seconds) if there is a large difference in diameter of front and rear tires. |
| 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 the following signals via CAN communication to transfer control unit. Vehicle speed signal Stop lamp switch signal (brake signal) |
| 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 engine speed signal via CAN communication to transfer control unit. |
COMPONENT FUNCTION CHART
Description
If the engine starts when there is a malfunction with 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 problem, start the self-diagnosis function. The 4WD warning lamp in the combination meter will indicate the problem area by flickering according to the self-diagnostic results. Refer to " DTC INDEX ".
The transfer control unit controls the transfer control device which controls shifts between 4H and 4LO and between 2WD and 4WD. When the vehicle battery is removed, the power supply to the transfer control unit is interrupted, and self-diagnosis memory function is suspended. DTC's P1801, P1811 or flash code 8 may also set when the power supply voltage for the transfer control unit is abnormally low while driving.
The transfer control unit controls the transfer control device which controls shifts between 4H and 4LO and between 2WD and 4WD. DTC P1802 - P1804 or P1809 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.
Flash code 5 may set when the following occurs
- 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 or flash code 2 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 or flash code 3 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 4LO switch detects that the transfer case is in 4LO range. DTC P1810 or flash code 6 will set when an improper signal from the 4LO switch is input due to an open or short circuit.
The 4WD shift switch allows the driver to select 2WD or 4WD and 4H or 4LO. DTC P1813 or flash code 9 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 or flash code 10 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 or flash code 11 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 or flash code 12 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 of flash code 13 will set if either of the following conditions exist
- Malfunction occurs in transfer control device drive circuit.
- Malfunction is detected in transfer shut off relay 1 and transfer shut off relay 2.
The ECM transmits the engine speed signal via CAN communication to the transfer control unit. DTC P1820 or flash code 7 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.
4WD warning lamp does not turn ON when turning ignition switch to ON.
4WD shift indicator lamp and 4LO indicator lamp do not turn ON for approx. 1 second 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 slowly while driving (1 time/2 seconds). The lamp continues to flash until the ignition switch is turned OFF.
The ATP indicator does not come on when the transfer is in neutral and the A/T lever is in neutral or, the ATP indicator stays on when the transfer case is not in neutral.