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U0121 Lost Communication With Anti-Lock Brake System (ABS) Control Module

AutoHex Online Help: Hyundai SANTAFE(CM) 2011
Component Location
General Description

CAN communication is a parallel circuit to interchange information among each units. CAN communication can share much information with units more faster and more efficiently by using specified language.

CAN-High line is twisted with CAN-Low line as a purpose in preventing from a noise.

ITM-ECU performs active control by sharing signals of engine RPM, APS, shift position, torque reduction.



DTC Description

This code related to communication line between ECU(ABS) and 4WD ECM(= TCCU : Transfer Case Control Unit) is set when CAN signal from ECU can't received for more than 1sec or ECU internal error occur.

If failure is detected ITM-ECU prohibits the ITM control and cuts the current to control coil.

DTC Detecting Condition

Item

Detecting Condition

Possible Cause

DTC Strategy

ABS-ITM Communication Line, or ECU side malfunction

Poor connection of each unit

Open or short in CAN communication circuit

Fault of each communication unit

CAN HIGH/LOW circuit open/short.

Faulty ABS.

Enable Conditions

IG KEY "ON" , ENGINE "ON "

Threshold Value

Loss of the 4D0H message for greater than 1 second

Diagnostic Time

1 sec.

MIL on condition

0.5 sec.

Fail Safe

Prohibiting ITM control

Dignostic Circuit Diagram
Signal Waveform & Data

Fig.1) CAN Signal : high & low