Diagnosis
Item 5: Diagnose when the M.U.T.-III cannot receive the data sent by ETACS-ECU.
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 ETACS-ECU" when the M.U.T.-III checks the periodically sent data from each ECU and cannot
receive the ETACS-ECU data only.
TROUBLE JUDGEMENT CONDITIONS
M.U.T.-III judges the trouble when the periodically sent data from ETACS-ECU cannot be
received.
PROBABLE CAUSES
- Damaged harness wires and connectors
- Power supply circuit malfunction of the ETACS-ECU
- Malfunction of the ETACS-ECU
DIAGNOSIS PROCEDURE
STEP 1. Connector check: joint connector (CAN1) and ETACS-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 (CAN1) and ETACS-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 the joint connector (CAN1) and the ETACS-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 (CAN1) terminal No.10 and ETACS-ECU connector terminal
No.56 OK: Continuity (2 Ω or less)
|
|
(5)Continuity between joint connector (CAN1) terminal No.21 and ETACS-ECU connector terminal
No.65 OK: Continuity (2 Ω or less)
caution |
Strictly observe the specified wiring harness repair procedure.
For details refer to .
|
|
Q.
Is the check result normal?
<All the resistances measure 2 Ω or less> Go to Step
3.
NO : <Either or all of the resistances measure more than 2 Ω> Repair
the wiring harness between joint connector (CAN1) and the ETACS-ECU connector.
STEP 3. Resistance measurement at ETACS-ECU connector.
caution |
A digital multimeter should be used. For details refer to .
|
|
(1)Remove the ETACS-ECU, and measure at the equipment side.
|
|
(2)Resistance at ETACS-ECU connector terminal Nos.56 and 65 OK: 120 ± 20 Ω
|
Q.
Is the check result normal?
<Within 120 ± 20 Ω> Power supply to the ETACS-ECU
may be suspected. Refer to
.
<Not within 120 ± 20 Ω> Replace the ETACS-ECU.