Diagnosis Item
6: Diagnose shorts in the power supply to CAN bus line (SUB). <Vehicles
with Automatic
A/C>
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 voltage of CAN_H or CAN_L line is more than 4.0
V.
TROUBLESHOOTING HINTS
- Malfunction of the wiring harness
- Malfunction of the connector
- Malfunction of the gateway-ECU <Vehicles with automatic
A/C>
- Malfunction of the A/C-ECU <Vehicles with automatic
A/C>
- Malfunction of the camera-ECU <Vehicles with multi around monitor
system>
- Malfunction of the headlamp automatic levelling-ECU <Vehicles with
auto
headlamp levelling system>
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STEP 1. Check the CAN bus lines. Voltage measurement at gateway-ECU
connector.
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caution |
A digital multimeter should be used. For details
refer to .
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caution |
The test wiring harness should be used. For details
refer
to .
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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 voltage
at the harness side of diagnosis connector.
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(2)Connect the negative battery terminal, and turn the
ignition switch to the "ON"
position.
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(3)Voltage between gateway-ECU connector terminal No.6
(CAN_H) and body earth. OK: 4.0 V or less
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(4)Voltage between gateway-ECU connector terminal No.5
(CAN_L) and body earth. OK: 4.0 V or less
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(5)Disconnect the negative battery terminal.
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Q.
Is the check result normal?
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<Both of the measurement
results show 4.0 V or less> Go to Step
10.
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<Either of CAN_H line
or CAN_L line the measurement
results show more than 4.0 V> Go to Step 2.
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STEP 2. Check the CAN line between joint connector (CAN4) and the
gateway-ECU. Voltage measurement at joint connector (CAN4).
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caution |
A digital multimeter should be used. For details
refer to .
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caution |
The test wiring harness should be used. For details
refer
to .
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Connect the negative battery terminal, and turn the
ignition switch to the "ON"
position.
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(3)Voltage between joint connector (CAN4) terminal No.10
(CAN_H) and body
earth. OK: 4.0 V or less
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(4)Voltage between joint connector (CAN4) terminal No.21
(CAN_L) and body
earth. OK: 4.0 V or less
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(5)Disconnect the negative battery terminal.
caution |
Strictly observe the specified wiring harness repair
procedure.
For details refer to .
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Q.
Is the check result normal?
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YES : <4.0 V or less> Go
to Step 3.
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NO : <More than 4.0 V> 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. Voltage measurement at joint connector
(CAN4).
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caution |
A digital multimeter should be used. For details
refer to .
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caution |
The test wiring harness should be used. For details
refer
to .
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Connect the negative battery terminal, and turn the
ignition switch to the "ON"
position.
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(3)Voltage between joint connector (CAN4) terminal No.1
(CAN_H) and body
earth. OK: 4.0 V or less
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(4)Voltage between joint connector (CAN4) terminal No.12
(CAN_L) and body
earth. OK: 4.0 V or less
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(5)Disconnect the negative battery terminal.
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Q.
Is the check result normal?
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<4.0 V or less> Go to
Step 6.
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<More than 4.0 V> 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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![](../../../img/54/ACF00701AC00ENG.png)
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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 levelling-ECU connector, and repair if necessary. If the
headlamp
levelling-ECU connector is in good condition, replace the headlamp
levelling-ECU (Refer to GROUP
54A - Headlamp Automatic levelling System, Headlamp levelling-ECU ).
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STEP 6. Check the CAN line between joint connector (CAN4) and the
camera-ECU. Voltage measurement at joint connector (CAN4).
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caution |
A digital multimeter should be used. For details
refer to .
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caution |
The test wiring harness should be used. For details
refer
to .
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Connect the negative battery terminal, and turn the
ignition switch to the "ON"
position.
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(3)Voltage between joint connector (CAN4) terminal No.3
(CAN_H) and body
earth. OK: 4.0 V or less
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(4)Voltage between joint connector (CAN4) terminal No.14
(CAN_L) and body
earth. OK: 4.0 V or less
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(5)Disconnect the negative battery terminal.
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Q.
Is the check result normal?
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<4.0 V or less> Go to
Step 9.
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<More than 4.0 V> Go
to Step 7.
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STEP 7. 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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![](../../../img/54/ACF00701AC00ENG.png)
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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 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 camera-ECU connector, and repair if necessary. If the camera-ECU
connector
is in good condition, replace the camera-ECU (Refer to GROUP 54A -
Camera System, Camera-ECU ).
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STEP 9. Check the CAN line between joint connector (CAN4) and the
A/C-ECU. Voltage measurement at joint connector (CAN4).
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caution |
A digital multimeter should be used. For details
refer to .
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caution |
The test wiring harness should be used. For details
refer
to .
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Connect the negative battery terminal, and turn the
ignition switch to the "ON"
position.
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(3)Voltage between joint connector (CAN4) terminal No.11
(CAN_H) and body
earth. OK: 4.0 V or less
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(4)Voltage between joint connector (CAN4) terminal No.22
(CAN_L) and body
earth. OK: 4.0 V or less
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(5)Disconnect the negative battery terminal.
caution |
Strictly observe the specified wiring harness repair
procedure.
For details refer to .
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Q.
Is the check result normal?
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<4.0 V or less> Repair
joint connector (CAN4).
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NO : <More than 4.0 V> Repair the
wiring harness between joint connector
(CAN4) and the A/C-ECU connector.
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STEP 10. 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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![](../../../img/54/ACF00701AC00ENG.png)
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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
12.
Check
the A/C-ECU connector, and repair if necessary. If the A/C-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 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 12. 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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![](../../../img/54/ACF00701AC00ENG.png)
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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 13.
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STEP 13. 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 (Refer to ).
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