Toyota Sienna Service Manual: Laser Sensor Power Source Circuit
DESCRIPTION
This circuit provides power to the laser sensor. The laser sensor emits radio waves towards an object in front and measures the distance and direction of the object by receiving the beam reflections. Based on the reflections, the sensor calculates the difference in speed between the vehicle and the object in front.
This data is transmitted to the distance control ECU. The ECM recognizes the laser sensor via terminals LGND. If an open circuit occurs in the wire harness between terminals LGND, the ECM cannot recognize the laser sensor. The ECM will stop the control of the vehicle-to-vehicle distance control mode and only the constant speed control mode can be used.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 CHECK DISTANCE CONTROL ECU (IGB VOLTAGE)
- Disconnect the L1 laser sensor connector.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
2 CHECK HARNESS AND CONNECTOR (LASER SENSOR - ECM AND BODY GROUND)
- Disconnect the E4 connector from the ECM.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
3 CHECK HARNESS AND CONNECTOR (LASER SENSOR - DISTANCE CONTROL ECU)
- Disconnect the D2 distance control ECU connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
REPLACE DISTANCE CONTROL ECU
Distance Control Switch Circuit
DESCRIPTION
The distance control switch sets the vehicle-to-vehicle distance mode. The
distance control switch is
installed in the steering pad switch. The vehicle-to-vehicle distance set value
...
Wiper Signal Circuit
DESCRIPTION
The distance control ECU detects wiper operation. If the windshield wipers
operate in the HI or LO mode,
the cruise control is canceled and the warning sound "pong" is emitte ...
Other materials:
Zero Point Calibration of Yaw Rate Sensor Undone
DESCRIPTION
The skid control ECU receives signals from the yaw rate sensor via CAN
communication system.
Yaw rate sensor has the built-in deceleration sensor.
If there is trouble in the bus lines between the yaw rate and deceleration
sensor and CAN communication
system, the DTC U0123 ...
Setting the vehicle speed
Press the “ON-OFF” button to
activate the cruise control.
Cruise control indicator will come
on*1 or will be displayed on the
multi-information display*2.
Press the button again to deactivate
the cruise control.
Accelerate or decelerate the
vehicle to the desired s ...
Terminals of ECU
1. CHECK POWER BACK DOOR ECU
Disconnect the P13 and P14 ECU connectors, and
check the voltage or resistance of each terminal of
the wire harness side connectors
If the result is not as specified, there may be a
malfunction on the wire harness side.
Reconnect the ECU connector ...
