Diagnosis Item 19: Diagnose when the M.U.T.-III cannot receive the data sent by CVT-ECU <CVT> or A/T-ECU <A/T>.



caution When servicing a CAN bus line, earth yourself by touching a metal object such as an unpainted water pipe. If you fail to do, a component connected to the CAN bus line may be broken.

FUNCTION




TROUBLE JUDGEMENT CONDITIONS




PROBABLE CAUSES



  • Damaged harness wires and connectors
  • Power supply circuit malfunction of the CVT-ECU <CVT> or A/T-ECU <A/T>
  • Malfunction of the CVT-ECU <CVT> or A/T-ECU <A/T>

DIAGNOSIS PROCEDURE


STEP 1. Connector check: joint connector (CAN1) and CVT-ECU <CVT> or A/T-ECU <A/T> connector


caution The strand end of the twist wire should be within 10 cm from the connector. For details refer to .
When checking the joint connector, ensure that its wiring harness side and its short pins are not damaged.

Q. Is the check result normal?

Go to Step 2.
Repair the defective connector. Replace the joint connector as necessary.

STEP 2. Resistance measurement at joint connector (CAN1) and CVT-ECU <CVT> or A/T-ECU <A/T> connector.


caution A digital multimeter should be used. For details refer to .
caution The test wiring harness should be used. For details refer to .
(1)Disconnect joint connector (CAN1) and the CVT-ECU <CVT> or A/T-ECU <A/T> connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the LOCK (OFF) position.
(3)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4)Continuity between joint connector (CAN1) terminal No.6 and CVT-ECU connector terminal No.4 <CVT>
OK: Continuity (2 Ω or less)
(5)Continuity between joint connector (CAN1) terminal No.17 and CVT-ECU connector terminal No.5 <CVT>
OK: Continuity (2 Ω or less)
(6)Continuity between joint connector (CAN1) terminal No.6 and CVT-ECU connector terminal No.10 <A/T>
OK: Continuity (2 Ω or less)
(7)Continuity between joint connector (CAN1) terminal No.17 and CVT-ECU connector terminal No.11 <A/T>
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

<All the resistances measure 2 Ω or less> Power supply to the CVT-ECU <CVT> or A/T-ECU <A/T> may be suspected. Diagnose the CVT or A/T. Refer to GROUP 23A - Troubleshooting <CVT> or GROUP 23C - Troubleshooting <A/T>.
NO : <Either or all of the resistances measure more than 2 Ω> Repair the wiring harness between joint connector (CAN1) and the CVT-ECU <CVT> or A/T-ECU <A/T> connector.