Transmission Control Systems

DTC U1000 CAN COMMUNICATION LINE

Description
Controller Area Network (CAN) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent malfunction 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 "CAN COMM CIRCUIT" with CONSULT-II or U1000 without CONSULT-II is detected when TCM cannot communicate to other control units.

Possible Cause
^ Harness or connectors (CAN communication line is open or shorted.)

DTC Confirmation Procedure

NOTE: If "DTC Confirmation Procedure" has been previously performed, always turn ignition switch OFF a wait at least 10 seconds before performing the next test.

After the repair, perform the following procedure to confirm the malfunction is eliminated.

WITH CONSULT-II





1. Turn ignition switch ON.
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 AT-109, "Diagnostic Procedure".

WITH GST
Follow the procedure "WITH CONSULT-II".

AT-CAN-01:

Wiring Diagram - AT - CAN





TCM terminals and data are reference value. Measured between each terminal and ground.

Diagnostic Procedure
1. CHECK CAN COMMUNICATION CIRCUIT

With CONSULT-II
1. Turn ignition switch ON and start engine.





2. Select "SELF-DIAG RESULTS" mode for "A/T" with CONSULT-II.
Is any malfunction of the "CAN COMM CIRCUIT" indicated?
YES >> Print out CONSULT-II screen, GO TO LAN section. Refer to LAN-4, "Precautions When Using CONSULT-II". Precautions When Using CONSULT-II
NO >> INSPECTION END