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DTC Logic
CAN (Controller Area Network) is a serial communication line for real time applications. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Modern vehicle is equipped with many electronic control unit, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN H-line, CAN L-line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.
CAN Communication Signal Chart. Refer to CAN Communication Signal Chart.
 
 
DTC DETECTION LOGIC
DTC No.M.U.T.-III SE screen items
(Trouble diagnosis content)
DTC Detection Condition
U2148-87CAN comm err (brake control unit)
[Controller area network communication error (brake control unit)]
Diagnosis conditionWhen ignition switch is ON.
Signal (terminal)CAN communication signal
ThresholdAir bag diagnosis sensor unit cannot communicate CAN communication signal.
Diagnosis delay time2 seconds or more.
 
 
POSSIBLE CAUSE
CAN communication system
 
 
FAIL-SAFE
 
 
DTC CONFIRMATION PROCEDURE
1.CHECK SELF-DIAG RESULT
With M.U.T.-III SE
  1. Ignition switch ON and wait for 2 seconds or more.
  2. Perform “Self Diagnostic Result” mode of “AIR BAG” using M.U.T.-III SE.
Is malfunctioning part detected?
-1To check malfunction symptom before repair: Refer to Intermittent IncidentIntermittent Incident.
-2Confirmation after repair: INSPECTION END