U1003 Code: Meaning, Causes, and Symptoms | OBD2 Codes

U1003 – Lost Communication With VVEL Control Module

 

U1003 Possible Symptoms

 

Engine Light ON (or Service Engine Soon Warning Light)

 

U1003 Possible Causes

 

Faulty Variable Valve Event & Lift (VVEL) Control Module,VVEL Control Module harness is open or shorted,VVEL Control Module circuit poor electrical connection,Faulty Engine Control Module (ECM)

 

U1003 Description

 

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Engine Control Module (ECM) and Variable Valve Event & Lift (VVEL) control module are connected with two communication lines (CAN H line and CAN L line) and transmit/receive data. ECM shares information and links with the VVEL control module during operation.