DTC 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. Many electronic control units are equipped onto a vehicle, 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.
DTC DETECTION LOGIC
| DTC | CONSULT screen terms (Trouble diagnosis content) | DTC detection condition | ||
| U0122 | 00 | VDC MDL (Lost communication with vehicle dynamics control module) | Diagnosis condition | Ignition switch ON |
| Signal (terminal) | CAN communication signal | |||
| Threshold | When ECM is not receiving CAN communication signal of OBD (emission related diagnosis) with ABS actuator and electric unit (control unit) | |||
| Diagnosis delay time | 2 seconds or more | |||
POSSIBLE CAUSE
Harness or connectors (CAN communication line is open or shorted)
FAIL-SAFE
Engine Control System
| Fail safe mode | Vehicle behavior | |
| Traveling control mode | Accelerator angle variation control | ECM controls the accelerator pedal depression speed to make it slower than actual speed. This causes a drop in accelerating performance and encourages the driver to repair malfunction.
NOTE:
|
| Combustion control mode | Stratified charge combustion control at starting | No stratified charge combustion at starting (cold start). |
Stop/Start System
When a DTC is detected, the stop/start indicator lamp blinks slowly and the stop/start system operation is prohibited. When ECM detects error while operating the stop/start system, ECM restarts the engine.
DTC Confirmation Procedure
- PERFORM DTC CONFIRMATION PROCEDURE
- Turn ignition switch ON and wait at least 3 seconds.
- Check 1st trip DTC.
Is 1st trip DTC detected?
YES>>
Refer to DTC Diagnosis Procedure .
NO>>
To check malfunction symptom before repair: Refer to Intermittent Incident .
NO>>
Confirmation after repair: INSPECTION END