U1000
DTC U1000 CAN COMMUNICATION LINEDescription
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.
On Board Diagnosis Logic
- This is an OBD-II self-diagnostic item.
Diagnostic trouble code A/T COMM LINE or U1000 with CONSULT-II and 12th judgement flicker without CONSULT-II is detected when TCM cannot communicate to other control unit.
Possible Cause
Harness or connectors
(CAN communication line is open or shorted.)
DTC Confirmation Procedure
NOTE:
If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Turn ignition switch to "ON" position. (Do not start engine.)
2. Select "DATA MONITOR" mode for "ENGINE" with CONSULT-II.
3. Start engine and wait for at least 6 seconds.
4. If DTC is detected, go to "Diagnostic Procedure" below.
WITH GST
Follow the procedure "WITH CONSULT-II".
WITHOUT CONSULT-II
1. Turn ignition switch "ON".
2. Wait at least 6 seconds or start engine and wait at least 6 seconds.
3. Perform self-diagnosis. Without Scan Tool
Wiring Diagram-AT-CAN
Diagnostic Procedure
1. CHECK CAN COMMUNICATION CIRCUIT
With CONSULT-II
1. Turn ignition switch to "ON" position. (Do not start engine.)
2. Select "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. The "CAN COMM CIRCUIT" is detected.
Yes or No
Yes >>Print out CONSULT-II screen, GO TO 2.
No >>INSPECTION END
2. CHECK CAN COMMUNICATION SIGNALS
CONSULT-II
1. Turn ignition switch to "ON" position. (Do not start engine.)
2. Select "CAN COMM SIGNALS" in "DATA MONITOR" mode for "A/T" with CONSULT-II.
>>Print out CONSULT-II screen, go to "CAN SYSTEM (FOR A/T MODELS)". Testing and Inspection
CAN Communication Signals