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Transfer Case (Diagnostic Codes & Circuit Tests) (Except Hybrid): Overview Toyota Highlander III

Transfer Case 7 illustrations ~480 words

DESCRIPTION

  1. The 4WD ECU assembly determines that the vehicle is turning based on the signals sent from the steering sensor.
  2. The steering sensor signal is sent to the 4WD ECU assembly via the CAN communication system.
DTC No.Detection ItemDTC Detection ConditionTrouble AreaMemory
C1297/97Steering Angle SensorWhen the voltage of 4WD ECU assembly IG terminal is 9.5 V or more, a steering sensor malfunction signal is received.Steering sensor CAN communication system 4WD ECU assembly Brake control systemDTC stored

The 4WD ECU assembly receives signals from each sensor to control clutch fluid pressure for limiting the center differential operation, which distributes torque according to the driving conditions.

DTC No.Detection ItemDTC Detection ConditionTrouble AreaMemory
C1298/98Linear Solenoid CircuitWhen all of the following continue for 1 second or more: The current requested by the 4WD linear solenoid (electro magnetic control coupling sub-assembly) is either 0 A or greater than 0.8 A. Open or short occurs in the linear solenoid circuit.Wire harness and connector 4WD linear solenoid (Electro magnetic control coupling sub-assembly) 4WD ECU assemblyDTC stored

Scheme 78

Scheme 78: WIRING DIAGRAM

This DTC is output if the heat generated by the Electro magnetic control coupling sub-assembly exceeds a certain amount or if the estimated oil temperature of the transfer exceeds a certain amount while driving.

DTC No.Detection ItemDTC Detection ConditionTrouble AreaMemory
C1299/99Cancellation of 4WD ControlWhen either of the following conditions is met: Condition that controls coupling calorific value is predefined value or more. Condition that transfer oil temperature is predefined value or more.Condition, size or tire pressure of the front or rear tires Suspension and ball joint Drive shaft Propeller shaft Electro magnetic control coupling sub-assembly 4WD ECU assemblyDTC stored

The 4WD ECU assembly outputs this DTC if a difference in tire size is detected.

DTC No.Detection ItemDTC Detection ConditionTrouble AreaMemory
C1337/91Diameter of the Tire is not UniformWhen the vehicle speed is 30 km/h or more, the difference between the average speed of the front and rear wheels is 4% or more for 36 seconds or more.Tire size or pressure (front and rear tires) Front speed sensor Rear speed sensor Front speed sensor rotor (Front drive shaft assembly) Rear speed sensor rotor (Rear axle hub and bearing assembly) Wire harness and connector Skid control ECU (Brake actuator assembly) 4WD ECU assemblyDTC stored

Scheme 79

Scheme 79: WIRING DIAGRAM

This DTC is output by the 4WD ECU assembly if a malfunction occurs in the linear solenoid power supply system.

DTC No.Detection ItemDTC Detection ConditionTrouble AreaMemory
C120C/79Linear Solenoid Power Supply System MalfunctionWhen one of the following conditions is met: When the 4WD relay is on, the 4WD relay monitor remains off for 1 second or more while the voltage at the IG1 terminal is 9.5 V or more When the 4WD relay is on, the 4WD relay monitor is not on for 1 second or more while the voltage at the IG1 terminal is less than 9.5 V While the 4WD relay is off, the 4WD relay monitor remains on for 1 second or more immediately after the ignition switch is turned to ONWire harness and connector (IG1 circuit, GND circuit) 4WD ECU assemblyDTC stored

Scheme 80

Scheme 80: WIRING DIAGRAM
  1. The 4WD ECU assembly inputs the signals sent from the ECM and skid control ECU (brake actuator assembly), and steering sensor via the CAN communication system.
  2. When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system before repairing each corresponding sensor.
DTC No.Detection ItemDTC Detection ConditionTrouble AreaMemory
U0073/86Control Module Communication Bus OFFWhen the following continues for 5 seconds or more: Signals from the 4WD ECU assembly are not received. When the following occurs 10 times consecutively: A communication malfunction (bus off) occurs one or more times within 0.1 seconds.CAN communication system 4WD ECU assemblyDTC stored
U0100/85Lost Communication with ECM / PCM "A"When both of the following continue for 2 seconds or more: The voltage of the IG1 terminal is 10 V or more. At a vehicle speed of 60 km/h (37 mph) or more, communication with the ECM cannot be performed.CAN communication system 4WD ECU assembly ECMDTC stored
U0126/84Lost Communication with Steering Angle Sensor ModuleWhen both of the following continue for 1 second or more: The voltage of the IG1 terminal is 10 V or more. Communication with the steering sensor cannot be performed. When all of the following occur 10 times consecutively: The voltage of the IG1 terminal is 10 V or more. The condition that communication with the steering sensor cannot be performed occurs once within 5 seconds. Occurs 10 times or more within 60 seconds.CAN communication system 4WD ECU assembly Steering sensorDTC stored
U0129/83Lost Communication with Brake System Control ModuleWhen both of the following continue for 3 seconds or more: The voltage of the IG1 terminal is 10 V or more. Communication with the skid control ECU (brake actuator assembly) cannot be performed.CAN communication system 4WD ECU assembly Skid control ECU (Brake actuator assembly)DTC stored

If a malfunction in the power source circuit occurs, or a malfunction in communication with the skid control ECU (brake actuator assembly) or in a speed sensor occurs, the 4WD ECU assembly will prohibit operations by the fail-safe function.

DTC No.Detection ItemDTC Detection ConditionTrouble AreaMemory
C1241/94Low Power Supply VoltageWhen the following continues for 10 seconds or more: At a vehicle speed of 3 km/h (2 mph) or more, voltage of IG1 terminal is 9.5 V or less. When either of the following is detected: With the IG1 terminal voltage 9.5 V or less, communication with the skid control ECU (brake actuator assembly) is impossible. Vehicle speed sensor voltage is reduced for 60 seconds or more. When the following continues for 3 seconds or more: With the IG1 terminal voltage 17 V or more, communication with the skid control ECU (brake actuator assembly) is impossible.Battery Charging system Wire harness and connector (IG1 circuit, GND circuit) Brake control system CAN communication system 4WD ECU assemblyDTC stored

Scheme 81

Scheme 81: WIRING DIAGRAM

If a malfunction in the ECM circuit occurs, the 4WD ECU assembly will output this DTC.

DTC No.Detection ItemDTC Detection ConditionTrouble AreaMemory
C1280/82Engine Circuit MalfunctionWhen the following continues for 5 seconds or more: Communication with engine control ECM is operating normally, but engine control system is malfunctioning.Engine control system 4WD ECU assemblyDTC stored

If a malfunction in the speed sensor signal circuit or acceleration sensor (airbag sensor assembly) circuit occurs, the 4WD ECU assembly will output this DTC.

The airbag sensor assembly has a built-in acceleration sensor.

DTC No.Detection ItemDTC Detection ConditionTrouble AreaMemory
C1296/96ABS MalfunctionWhen one of the following conditions is met: Wheel speed sensor malfunction is received from the skid control ECU (brake actuator assembly) Acceleration sensor (airbag sensor assembly) malfunction is received from skid control ECU (brake actuator assemblyBrake control system Skid control ECU (Brake actuator assembly) Acceleration sensor (airbag sensor assembly) circuit 4WD ECU assemblyDTC stored

The 4WD ECU assembly is connected to the combination meter assembly via the CAN communication system. If any of the following conditions are detected, the multi-information display indicates a malfunction in the dynamic torque control AWD system.

  1. There is a malfunction in the 4WD ECU assembly internal circuit.
  2. A low voltage is applied to the power source for the 4WD ECU assembly.
  3. There is a malfunction in the CAN communication system.
  4. There is a malfunction in the brake control system.
  5. During fail-safe function.

Scheme 82

Scheme 82: WIRING DIAGRAM

Refer to "AWD Warning Remains ON".

Refer to AWD Warning Remains ON [12/2013 - ]

Connecting terminals TC and CG of the DLC3 causes the 4WD ECU assembly to display a DTC on the multi-information display.

HINT

When each warning light remains blinking, a short to ground in the wiring of terminal TC of the DLC3 or an internal short to ground in each ECU is suspected.

Scheme 83

Scheme 83: WIRING DIAGRAM

The 4WD ECU assembly changes the control mode in response to "Auto Mode" and "Lock Mode" signals from the AWD lock switch (differential lock switch).

Scheme 84

Scheme 84: WIRING DIAGRAM