Dynamic Radar Cruise Control System

CRUISE CONTROL: DYNAMIC RADAR CRUISE CONTROL SYSTEM: U1102: Lost Communication with Radar Sensor

DTC U1102 - Lost Communication with Radar Sensor

DESCRIPTION

The millimeter wave radar sensor and distance control ECU (cruise control ECU) transmit the data for general vehicle control and diagnosis function along the communication line. The distance control ECU (cruise control ECU) determines the presumed R information based on the signal from the steering wheel and yaw rate sensor. The distance control ECU (cruise control ECU) transmits the current vehicle speed and presumed R information to the millimeter wave radar sensor.






WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
- When the distance control ECU is replaced with a new one, initialization must be performed Installation.
- When the millimeter wave radar sensor is replaced with a new one, adjustment of the radar sensor beam axis must be performed Adjustments.

PROCEDURE

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





(a) Disconnect the distance control ECU and millimeter wave radar sensor connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE WIRE HARNESS AND CONNECTOR
OK -- Continue to next step.
2. CHECK DISTANCE CONTROL ECU





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






NG -- REPLACE DISTANCE CONTROL ECU
OK -- Continue to next step.
3. CHECK MILLIMETER WAVE RADAR SENSOR





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










(b) Check the signal waveform between terminal LRRD (B8-4) of the millimeter wave radar sensor and body ground.
OK:
A waveform similar to that in the illustration on the left is output.
HINT:
- Gauge set: 2 V/DIV., 5 msec./DIV.
- Condition: Engine switch on (IG)

NG -- REPLACE MILLIMETER WAVE RADAR SENSOR
OK -- END (INTERMITTENT PROBLEM IS PRESENT)