Diagnosis Item
13: Diagnose when the M.U.T.-III cannot receive the data sent by 4WD-ECU <4WD>.
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 4WD-ECU" when the M.U.T.-III checks the periodically sent data from each ECU and cannot
receive the 4WD-ECU data only.
TROUBLE JUDGEMENT CONDITIONS
M.U.T.-III judges the trouble when the periodically sent data from 4WD-ECU cannot be received.
PROBABLE CAUSES
Damaged harness wires and connectors
Power supply circuit malfunction of the 4WD-ECU
Malfunction of the 4WD-ECU
DIAGNOSIS PROCEDURE
STEP 1. Connector check: joint connector (CAN-3) and 4WD-ECU
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 (CAN3) and 4WD-ECU
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 (CAN3) and the 4WD-ECU 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 (CAN3) terminal No.5 and 4WD-ECU connector terminal
No.5 OK: Continuity (2 Ω or less)
(5)Continuity between joint connector (CAN3) terminal No.16 and 4WD-ECU connector
terminal No.13 OK: Continuity (2 Ω or less)
Q.
Is the check result normal?
<All the resistances measure 2 Ω or less> Power supply
to the 4WD-ECU may be suspected. Diagnose the electronic control 4WD. Refer to GROUP 27C - Troubleshooting .
NO : <Either or all of the resistances measure more than 2 Ω> Check
the intermediate connector, and repair if necessary. If the intermediate connector is in good condition,
repair the wiring harness between joint connector (CAN3) and the 4WD-ECU connector.