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C-CAN Inspection

Inspection Item Inspection Condition (+) Probe (-) Probe Specification
Connector Terminal Connector Terminal
Resistance inspection (ICU, CLU
  1. Ignition "OFF".
  2. Disconnect the connector(s) ICU, CLU.
 ICU (component side) 11 (C-CAN high) ICU (component side) 10 (C-CAN low) Approx. 120Ω
CLU (component side) 32 (C-CAN high) CLU (component side) 33 (C-CAN low) Approx. 120Ω
Open in Circuit Inspection (ICU ↔ MDPS)
  1. Ignition "OFF".
  2. Disconnect the connector(s) ICU, MDPS.
 ICU connector 11 (C-CAN high) MDPS connector 7 (C-CAN high) Approx. below 1Ω
ICU connector 10 (C-CAN low) MDPS connector 8 (C-CAN low) Approx. below 1Ω
C-CAN oscilloscope (MDPS)
  1. Ignition "ON".
 MDPS connector 7 (C-CAN high) Chassis ground - Fig.1 to 6
MDPS connector 8 (C-CAN low) Chassis ground -

Information 

It is important to check CAN high and low at the same time to check the waveform of the CAN communication line. The CAN signal is in a bus idle state based on 2.5V (digital "1"), the high signal rises to 3.5V, the low signal falls to 1.5V, and the voltage difference between the high and low signals is "0" when 2V occurs. Is detected. In addition, it monitors whether the high and low signals have opposite voltages based on 2.5V like the waveform on the left, and monitors whether the current CAN signal is transmitted normally. In CAN communication, a continuous "0" signal of 6 bits or more means occurrence of an error. 1 bit can be easily determined by obtaining the time when "SOF" (Start Of Frame), indicating the start of the frame, occurs. Check if the "0" signal of 6 bits or more occurs continuously during CAN communication waveform check.

  1. Reference voltage about 2.5V (high: 2.5V → 3.5V rise, low: 2.5V → 1.5V drop)
  2. Idle (2.5V) section of a certain period
  3. Constant data frame time
  4. High and low symmetrical frame shape
    G16094576Courtesy of KIA MOTORS AMERICA, INC.
    G16094577Courtesy of KIA MOTORS AMERICA, INC.
    G16060120Courtesy of KIA MOTORS AMERICA, INC.
    G16060121Courtesy of KIA MOTORS AMERICA, INC.
    G16060122Courtesy of KIA MOTORS AMERICA, INC.
    G16060123Courtesy of KIA MOTORS AMERICA, INC.

    Good 

    • Go to "COMPONENT INSPECTION" procedure.

    No Good 

    • Check and repair CAN lines for open circuits or short circuits, go to "COMPONENT INSPECTION" procedure.
    • Repair or replace as necessary and then go to "VERIFICATION OF REPAIR" procedure.
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