Dynamic Radar Cruise Control System - Millimeter Wave Radar Sensor Power Source Circuit

Lexus IS250 IS220d GSE20 ALE20 - CRUISE CONTROL

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK DISTANCE CONTROL ECU (IGB VOLTAGE)

CHECK WIRE HARNESS (MILLIMETER WAVE RADAR SENSOR - ECM AND BODY GROUND)

CHECK WIRE HARNESS (MILLIMETER WAVE RADAR SENSOR - DISTANCE CONTROL ECU)

DYNAMIC RADAR CRUISE CONTROL SYSTEM - Millimeter Wave Radar Sensor Power Source Circuit

DESCRIPTION

This circuit provides power to the millimeter wave radar sensor. The millimeter wave radar 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 (cruise control ECU). The ECU recognizes the millimeter wave radar sensor via terminals LGND. If an open circuit occurs in the wire harness between terminals LGND, the ECM cannot recognize the millimeter wave radar 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

Dynamic Radar Cruise Control System - Millimeter Wave Radar Sensor Power Source Circuit. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

1.CHECK DISTANCE CONTROL ECU (IGB VOLTAGE)
Dynamic Radar Cruise Control System - Millimeter Wave Radar Sensor Power Source Circuit. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Disconnect the B9 sensor connector.

Measure the voltage according to the value(s) in the table below.

  • Standard voltage:
  • Tester ConnectionConditionSpecified Condition
    B9-5 (IGB) - Body groundEngine switch on (IG)10 to 14 V
NG
Go to step 3
OK
2.CHECK WIRE HARNESS (MILLIMETER WAVE RADAR SENSOR - ECM AND BODY GROUND)
Dynamic Radar Cruise Control System - Millimeter Wave Radar Sensor Power Source Circuit. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Disconnect the B9 sensor connector.

Disconnect the A5 ECM connector.

Measure the resistance according to the value(s) in the table below.

  • Standard resistance:
  • Tester ConnectionSpecified Condition
    A5-29 (LGND) - B9-1 (LGND)Below 1 Ω
    B9-1 (LGND) - Body ground10 kΩ or higher
    B9-2 (SGND) - Body groundBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
3.CHECK WIRE HARNESS (MILLIMETER WAVE RADAR SENSOR - DISTANCE CONTROL ECU)
Dynamic Radar Cruise Control System - Millimeter Wave Radar Sensor Power Source Circuit. CRUISE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Disconnect the B9 sensor connector.

Disconnect the J17 ECU connector.

Measure the resistance according to the value(s) in the table below

  • Standard resistance:
  • Tester ConnectionSpecified Condition
    B9-5 (IGB) - J17-13 (IGB)Below 1 Ω
    J17-13 (IGB) - Body ground10 kΩ or higher
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE