Diagnosis Item
7: Diagnose shorts in the earth to CAN bus line (SUB).
| 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.
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TROUBLE JUDGEMENT CONDITIONS
The M.U.T.-III judges the trouble
when it is impossible to receive the periodically sent
data and the resistance of CAN_H or CAN_L line is less than 1.0
V.
TROUBLESHOOTING HINTS
- Malfunction of the wiring harness
- Malfunction of the connector
- Malfunction of the gateway-ECU
- Malfunction of the A/C-ECU
- Malfunction of the camera-ECU <Vehicles with multi around monitor
system>
- Malfunction of the headlamp automatic levelling-ECU <Vehicles with
headlamp
automatic levelling System>
- Malfunction of the gateway-ECU (for smartphone link display
audio)
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STEP 1. Check the CAN bus lines. Resistance measurement
at gateway-ECU connector.
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| caution |
- A digital multimeter should
be used. For details refer to service precautions.
- The test wiring harness should be used. For details refer to
service precautions.
- When measuring the resistance, disconnect the negative battery
terminal. For details
refer to service precautions.
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| note |
This inspection allows you to check that there is a
short to power supply in either CAN_H
line or CAN_L line. Thus, in the following steps, check the CAN
bus line that is defective.
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(1)Disconnect A/C-ECU connector and gateway-ECU connector,
and measure the resistance
at the harness side of gateway-ECU connector.
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(2)Ensure that the negative battery terminal is
disconnected.
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(3)Resistance between gateway-ECU connector terminal No.6
(CAN_H) and body
earth.
OK: 1 kΩ or more
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(4)Resistance between gateway-ECU connector terminal No.5
(CAN_L) and body
earth.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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 <Both of the measurement
results show 1 kΩ or more> Go
to Step 13.
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 <Either of CAN_H line
or CAN_L line the measurement
results show less than 1 kΩ> Go to Step 2.
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STEP 2. Check the CAN line between joint connector (CAN4) and the
gateway-ECU. Resistance measurement at joint connector
(CAN4).
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| caution |
- A digital multimeter should
be used. For details refer to service precautions.
- The test wiring harness should be used. For details refer to
service precautions.
- When measuring the resistance, disconnect the negative battery
terminal. For details
refer to service precautions.
- Strictly observe the specified wiring harness repair procedure. For
details refer
to service precautions.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Ensure that the negative battery terminal is
disconnected.
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(3)Resistance between joint connector (CAN4) terminal No.10
(CAN_H) and body
earth.
OK: 1 kΩ or more
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(4)Resistance between joint connector (CAN4) terminal No.21
(CAN_L) and body
earth.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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YES <Vehicles with headlamp automatic
levelling system> : <1 kΩ or
more> Go to Step 3.
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YES <Vehicles without headlamp automatic
levelling system> : <1 kΩ or
more> Go to Step 6.
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NO : <Less than 1 kΩ> Repair
the wiring harness between joint
connector (CAN4) and the gateway-ECU connector.
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STEP 3. Check the CAN line between joint connector (CAN4) and the
headlamp automatic levelling-ECU. Resistance measurement at joint
connector (CAN4).
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| caution |
- A digital multimeter should
be used. For details refer to service precautions.
- The test wiring harness should be used. For details refer to
service precautions.
- When measuring the resistance, disconnect the negative battery
terminal. For details
refer to service precautions.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Ensure that the negative battery terminal is
disconnected.
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(3)Resistance between joint connector (CAN4) terminal No.1
(CAN_H) and body
earth.
OK: 1 kΩ or more
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(4)Resistance between joint connector (CAN4) terminal No.12
(CAN_L) and body
earth.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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<1 kΩ or more>
Go to Step 6.
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<Less than 1 kΩ
> Go to Step 4.
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STEP 4. M.U.T.-III CAN bus diagnostics [Headlamp automatic
levelling-ECU connector
disconnected]
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(1)Disconnect headlamp automatic levelling-ECU connector, and
diagnose by using the
M.U.T.-III.
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(2)Diagnose CAN bus lines, and check if
M.U.T.-III screen is as shown in the illustration.
Q.
Does M.U.T.-III screen correspond to the illustration?
Repair the wiring harness between
joint connector (CAN4) and the headlamp automatic levelling-ECU
connector.
Check the headlamp automatic
levelling-ECU connector, and repair if necessary.
If the headlamp automatic levelling-ECU connector is in good condition, go
to Step 5.
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STEP 5. M.U.T.-III CAN bus diagnostics (retest the
system)
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Diagnose CAN bus lines, and check if M.U.T.-III
screen shows normal state.
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Q.
Is the check result normal?
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The
trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Use Troubleshooting/inspection Service Points - How to Cope
with Intermittent
Malfunction).
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Check
the headlamp automatic levelling-ECU connector, and repair if necessary.
If the headlamp automatic levelling-ECU connector is in good condition,
replace the headlamp
automatic levelling-ECU (Refer to GROUP 54A - Headlamp Automatic
Levelling System,
Headlamp Automatic Levelling-ECU).
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STEP 6. Check the CAN line between joint connector (CAN4) and the
gateway-ECU (for smartphone link display audio). Resistance measurement at
joint connector (CAN4).
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| caution |
- A digital multimeter should
be used. For details refer to service precautions.
- The test wiring harness should be used. For details refer to
service precautions.
- When measuring the resistance, disconnect the negative battery
terminal. For details
refer to service precautions.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Ensure that the negative battery terminal is
disconnected.
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(3)Resistance between joint connector (CAN4) terminal No. 2
(CAN_H) and body
earth.
OK: 1 kΩ or more
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(4)Resistance between joint connector (CAN4) terminal No. 13
(CAN_L) and
body earth.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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YES <Vehicles with multi around monitor
system> :
<1 kΩ or more> Go to Step 9.
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YES <Vehicles without multi around
monitor system> : <1 kΩ or
more> Go to Step 12.
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<Less than 1 kΩ
> Go to Step 7.
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STEP 7. M.U.T.-III CAN bus diagnostics [Gateway-ECU (for
smartphone
link display audio) connector disconnected]
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(1)Disconnect gateway-ECU (for smartphone link display audio)
connector, and diagnose
by using the M.U.T.-III.
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(2)Diagnose CAN bus lines, and check if
M.U.T.-III screen is as shown in the illustration.
Q.
Does M.U.T.-III screen correspond to the illustration?
Repair the wiring harness between
joint connector (CAN4) and the gateway-ECU (for
smartphone link display audio) connector.
Check the gateway-ECU (for
smartphone link display audio) connector, and repair
if necessary. If the gateway-ECU (for smartphone link display audio)
connector is in good condition,
go to Step 8.
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STEP 8. M.U.T.-III CAN bus diagnostics (retest the
system)
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Diagnose CAN bus lines, and check if M.U.T.-III
screen shows normal state.
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Q.
Is the check result normal?
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The
trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Use Troubleshooting/inspection Service Points - How to Cope
with Intermittent
Malfunction).
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Check
the gateway-ECU (for smartphone link display audio) connector, and repair
if necessary. If the gateway-ECU (for smartphone link display audio)
connector is in good condition,
replace the gateway-ECU (for smartphone link display audio) (Refer to GROUP
54A - Smartphone
Link Display Audio  ).
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STEP 9. Check the CAN line between joint connector (CAN4) and the
camera-ECU. Resistance measurement at joint connector
(CAN4).
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| caution |
- A digital multimeter should
be used. For details refer to service precautions.
- The test wiring harness should be used. For details refer to
service precautions.
- When measuring the resistance, disconnect the negative battery
terminal. For details
refer to service precautions.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Ensure that the negative battery terminal is
disconnected.
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(3)Resistance between joint connector (CAN4) terminal No.3
(CAN_H) and body
earth.
OK: 1 kΩ or more
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(4)Resistance between joint connector (CAN4) terminal No.14
(CAN_L) and body
earth.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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<1 kΩ or more>
Go to Step 12.
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<Less than 1 kΩ
> Go to Step 10.
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STEP 10. M.U.T.-III CAN bus diagnostics [Camera-ECU connector
disconnected]
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(1)Disconnect camera-ECU connector, and diagnose by using the
M.U.T.-III.
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(2)Diagnose CAN bus lines, and check if
M.U.T.-III screen is as shown in the illustration.
Q.
Does M.U.T.-III screen correspond to the illustration?
Repair the wiring harness between
joint connector (CAN4) and the camera-ECU connector.
Check the
camera-ECU connector, and repair if necessary. If the camera-ECU connector
is in good condition, go to Step 11.
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STEP 11. M.U.T.-III CAN bus diagnostics (retest the
system)
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Diagnose CAN bus lines, and check if M.U.T.-III
screen shows normal state.
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Q.
Is the check result normal?
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The
trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Use Troubleshooting/inspection Service Points - How to Cope
with Intermittent
Malfunction).
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Check
the camera-ECU connector, and repair if necessary. If the camera-ECU
connector
is in good condition, replace the camera-ECU (Refer to GROUP 54A -
Multi Around Monitor,
Camera-ECU).
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STEP 12. Check the CAN line between joint connector (CAN4) and the
A/C-ECU. Resistance measurement at joint connector (CAN4).
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| caution |
- A digital multimeter should
be used. For details refer to service precautions.
- The test wiring harness should be used. For details refer to
service precautions.
- When measuring the resistance, disconnect the negative battery
terminal. For details
refer to service precautions.
- Strictly observe the specified wiring harness repair procedure. For
details refer
to service precautions.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Ensure that the negative battery terminal is
disconnected.
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(3)Resistance between joint connector (CAN4) terminal No.11
(CAN_H) and body
earth.
OK: 1 kΩ or more
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(4)Resistance between joint connector (CAN4) terminal No.22
(CAN_L) and body
earth.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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<1 kΩ or more>
Repair joint connector (CAN4).
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NO : <Less than 1 kΩ > Repair
the wiring harness between joint
connector (CAN4) and the A/C-ECU connector.
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STEP 13. M.U.T.-III CAN bus diagnostics [A/C-ECU connector
disconnected]
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(1)Disconnect A/C-ECU connector and diagnose by using the
M.U.T.-III.
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(2)Diagnose CAN bus lines, and check if
M.U.T.-III screen is as shown in the illustration.
Q.
Does M.U.T.-III screen correspond to the illustration?
Go to Step
15.
Check
the A/C-ECU connector, and repair if necessary. If the A/C-ECU connector
is in good condition, go to Step 14.
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STEP 14. M.U.T.-III CAN bus diagnostics (retest the
system)
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Diagnose CAN bus lines, and check if M.U.T.-III
screen shows normal state.
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Q.
Is the check result normal?
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The
trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Use Troubleshooting/inspection Service Points - How to Cope
with Intermittent
Malfunction).
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Check
the A/C-ECU connector, and repair if necessary. If the A/C-ECU connector
is in good condition, replace the A/C-ECU (Refer to GROUP 55B -
Heater Control Unit).
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STEP 15. M.U.T.-III CAN bus diagnostics [Gateway-ECU connector
disconnected]
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(1)Disconnect gateway-ECU connector, and diagnose by using
the M.U.T.-III.
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(2)Diagnose CAN bus lines, and check if
M.U.T.-III screen is as shown in the illustration.
Q.
Does M.U.T.-III screen correspond to the illustration?
The trouble can be an intermittent
malfunction (Refer to GROUP 00 - How
to Use Troubleshooting/inspection Service Points - How to Cope
with Intermittent
Malfunction).
Check the gateway-ECU connector,
and repair if necessary. If the gateway-ECU connector
is in good condition, go to Step 16.
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STEP 16. M.U.T.-III CAN bus diagnostics (retest the
system)
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Diagnose CAN bus lines, and check if M.U.T.-III
screen shows normal state.
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Q.
Is the check result normal?
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The
trouble can be an intermittent malfunction (Refer to GROUP 00 - How
to Use Troubleshooting/inspection Service Points - How to Cope
with Intermittent
Malfunction).
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Check
the gateway-ECU connector, and repair if necessary. If the gateway-ECU
connector
is in good condition, replace the gateway-ECU.
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