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
The diagnostic result demonstrates that "the M.U.T.-III cannot receive the sent data from
the CVT-ECU <CVT> or A/T-ECU <A/T>" when the M.U.T.-III checks the periodically sent
data from each ECU and cannot receive the CVT-ECU <CVT> or A/T-ECU <A/T> data only.
TROUBLE JUDGEMENT CONDITIONS
M.U.T.-III judges the trouble when the periodically sent data from CVT-ECU <CVT> or
A/T-ECU <A/T> cannot be received.
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.