Active Torque Control 4WD System (Diagnostics - Introduction): Other Toyota Venza I facelift

PRECAUTION [08/2013 - ]

1. PRECAUTION FOR DISCONNECTING THE BATTERY CABLE NOTE: When disconnecting the cable from the negative (-) battery terminal, initialize the following systems after the cable is reconnected: System See Procedure Back Door Closer System Refer to «INITIALIZATION [08/2013 - ]»(ref-649249-S21669950452014081400000) Power Back Door System Refer to «INITIALIZATION [08/2013 - ]»(ref-649249-S21669950452014081400000)
2. TROUBLESHOOTING PRECAUTION NOTE: Since the Active Torque Control 4WD system may be influenced by a malfunction in other systems, be sure to check for DTCs in the other systems. When removing and installing the AWD control ECU and each sensor, be sure to check that the normal display is output in test mode inspection and in DTC output inspection after installing all the parts. If the DTC of the CAN communication line is output, repair the malfunction in the communication line and troubleshoot the Active Torque Control 4WD system. Since the CAN communication line has its own length and route, it cannot be repaired temporarily with a bypass wire, etc.

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COMMUNICATION TABLE

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1. FUNCTION OF MAIN COMPONENTS Component Function Accessory Meter Assembly AWD Warning Light Illuminates to warn the driver of a malfunction in the active torque control 4WD system. Blinks to inform the driver of the DTCs in diagnostic mode. Speed Sensors (4) Detects the wheel speed of each wheel. Crankshaft Position Sensor Detects the engine speed and outputs it to the ECM. Throttle Position Sensor Detects the throttle valve position and outputs it to the ECM. Park/Neutral Position Switch Assembly Detects the shift position of the transaxle and outputs it to the ECM. Stop Light Switch Assembly Detects when the brake pedal is depressed. Parking Brake Switch Assembly Detects when the parking brake is applied. Deceleration Sensor Detects the vehicle's longitudinal acceleration and deceleration Transfer Drive force input into the differential is redirected 90 degrees and output to the propeller shaft by the transfer. Rear Differential Electromagnetic Control Coupling - Electromagnetic Solenoid Distributes drive torque in accordance with the amperage applied by the AWD control ECU. AWD Control ECU Controls the amperage applied to the electromagnetic solenoid based on signals provided by the sensors in order to optimally distribute drive torque in accordance with driving conditions. Turns AWD mode off when a parking brake ON signal is received from the main body ECU (instrument panel junction block). Turns AWD mode off when a shift position signal (P or N) is received from the ECM. ECM Outputs signals such as the shift position signal, throttle position signal, and crankshaft position signal to the AWD control ECU. Skid Control ECU Outputs signals such as the vehicle speed signal and deceleration signal to the AWD control ECU. Main Body ECU (Instrument Panel Junction Block) Outputs signals such as the parking brake signal to the AWD control ECU.
2. OPERATION 2WD Mode The drive force is transmitted from the propeller shaft to the front housing. The AWD control ECU judges whether it is necessary to send drive torque to the rear wheels based on input from various sensors. When it is not necessary to send drive torque to the rear wheels, the electromagnetic solenoid is not operated. The drive force of the front housing is not transmitted to the shaft because the control clutch is not engaged. Accordingly, drive force from the propeller shaft is not transmitted to the rear wheels. AWD Mode The drive force is transmitted from the propeller shaft to the front housing. The AWD control ECU judges whether it is necessary to send drive torque to the rear wheels based on input from various sensors. When it is necessary to send drive torque to the rear wheels, the electromagnetic solenoid is operated. It attracts the armature to the control clutch side. This causes the control clutch to engage and the cam to rotate. The rotational movement of the cam causes the piston to push on the main clutch, causing the main clutch to engage. The amount of drive force that is transmitted to the rear wheels is controlled steplessly by controlling the amperage that is applied to the electromagnetic solenoid. Accordingly, drive force from the propeller shaft is transmitted to the rear wheels.

FAIL-SAFE CHART [08/2013 - ]

1. FAIL-SAFE FUNCTION If the following malfunctions occur, the AWD control ECU will stop the function of 4WD control system or partly change the function to control the system. If a malfunction occurs in the sensor signal or actuator, the flow of electricity to the electromagnetic solenoid of the electromagnetic control coupling is prohibited. As a result, the system enters front wheel drive condition. When a component of the system malfunctions and the fail-safe function activate, the component operation is prohibited. However, if the system is controlling the component and the fail-safe function activates, the system operation is gradually stopped to prevent sudden changes in the vehicle condition. When system control is not possible, the warning light is illuminated to stop operation of the system operation.