Pre-Collision System

PRE-COLLISION SYSTEM:

DTC U0122 - Lost Communication with Vehicle Dynamics Control Module

DESCRIPTION

The seat belt control ECU receives signals from the skid control ECU, center airbag sensor assembly, and distance control ECU via CAN communication system.
The distance control ECU receives signals from the ECM via CAN communication system.





HINT: When two or more DTCs starting with "U" are output simultaneously, inspect the connectors and wire harness of each ECU.

INSPECTION PROCEDURE

NOTICE:
- Turn the engine switch off before measuring the resistances of CAN bus main wire and CAN bus branch wires.
- After the engine switch is turned off, check that the key reminder warning system and light reminder warning system are not in operation.
- Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the engine switch, any other switches, or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

PROCEDURE

1. CHECK OPEN IN CAN NO. 1 BUS WIRE (SKID CONTROL ECU BRANCH WIRE)
(a) Turn the engine switch off.
(b) Disconnect the skid control ECU connector.





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






NG -- REPAIR OR REPLACE CAN NO. 1 BUS BRANCH WIRE OR CONNECTOR (SKID CONTROL ECU)
OK -- Continue to next step.
2. CHECK WIRE HARNESS (IG1, GND1, GND2)





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





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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE BRAKE ACTUATOR