Diagnosis Item
8: Diagnose shorts between CAN_H and L lines (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
When all of the following conditions are met,
the M.U.T.-III determines that a short circuit
is present between CAN_L and CAN_H lines.
- The M.U.T.-III cannot receive the periodic transmission
data from any ECUs.
- The voltage between CAN sub bus lines (CAN_L and CAN_H lines)
is 1.0 V or more, 4.0 V or less.
- The resistance at CAN sub bus line (CAN_L and CAN_H lines) is
2 Ω or less.
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>
- Malfunction of the smartphone link display audio <Vehicles for
RUSSIA,
AUSTRALIA and NEW ZEALAND>
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STEP 1. Connector check: joint connector (CAN4)
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| caution |
The strand end of the twist wire should be within
10 cm from
the connector.
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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 a defective connector or
replace the joint connector.
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STEP 2. Resistance measurement at joint connector (CAN4).
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| caution |
A digital multimeter should be used.
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| caution |
The test wiring harness should be used.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Turn the ignition switch to the "LOCK" (OFF)
position.
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(3)
| caution |
When measuring the resistance, disconnect the
negative battery
terminal.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN4) terminal Nos.10
and 21.
OK: 120 ± 20 Ω
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Q.
Is the check result normal?
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YES  : <Within 120 ± 20
Ω> Go to Step 4.
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NO : <Not within 120 ±
20 Ω> Go to Step 3.
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STEP 3. Resistance measurement at gateway-ECU connector.
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| caution |
A digital multimeter should be used.
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(1)Remove the gateway-ECU, and measure at the equipment
side.
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(2)Resistance between gateway-ECU connector terminal Nos.5
and 6.
OK: 120 ± 20 Ω
| caution |
Strictly observe the specified wiring harness repair
procedure.
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Q.
Is the check result normal?
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<Within 120 ± 20
Ω> Check intermediate connector, and
repair if necessary. If the intermediate connector is in good condition,
repair the wiring harness between
joint connector (CAN4) and the gateway-ECU connector.
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<Not within 120 ± 20
Ω> 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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STEP 4. Resistance measurement at joint connector (CAN4).
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| caution |
A digital multimeter should be used.
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| caution |
The test wiring harness should be used.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Turn the ignition switch to the "LOCK" (OFF)
position.
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(3)
| caution |
When measuring the resistance, disconnect the
negative battery
terminal.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN4) terminal Nos.1
and 12.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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YES : <1 kΩ or
more> Go to Step 6.
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<Less than 1
kΩ> Go to Step 5.
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STEP 5. Resistance measurement at headlamp automatic levelling-ECU
connector.
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| caution |
A digital multimeter should be used.
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(1)Remove the headlamp automatic levelling-ECU, and measure
at the equipment side.
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(2)Resistance between headlamp automatic levelling-ECU
connector terminal Nos.6 and
13.
OK: 1 kΩ or more
| caution |
Strictly observe the specified wiring harness repair
procedure.
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Q.
Is the check result normal?
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<1 kΩ or more>
Repair the wiring harness between joint
connector (CAN4) and the headlamp automatic levelling-ECU
connector.
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<Less than 1 kΩ>
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 Levelling-ECU).
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STEP 6. Resistance measurement at joint connector (CAN4).
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| caution |
A digital multimeter should be used.
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| caution |
The test wiring harness should be used.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Turn the ignition switch to the "LOCK" (OFF)
position.
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(3)
| caution |
When measuring the resistance, disconnect the
negative battery
terminal.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN4) terminal Nos.2
and 13.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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YES : <1 kΩ or
more> Go to Step 8.
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<Less than 1
kΩ> Go to Step 7.
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STEP 7. Resistance measurement at smartphone link display audio
connector.
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| caution |
A digital multimeter should be used.
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(1)Remove the smartphone link display audio, and measure at
the equipment side.
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(2)Resistance between smartphone link display audio connector
terminal Nos.3 and 13.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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<1 kΩ or more>
Repair the wiring harness between joint
connector (CAN4) and the smartphone link display audio connector.
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<Less than 1 kΩ>
Check the smartphone link display audio
connector, and repair if necessary. If the smartphone link display audio
connector is in good condition,
replace the smartphone link display audio (Refer to GROUP 54A -
Smartphone Link Display Audio  ).
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STEP 8. Resistance measurement at joint connector (CAN4).
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| caution |
A digital multimeter should be used.
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| caution |
The test wiring harness should be used.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Turn the ignition switch to the "LOCK" (OFF)
position.
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(3)
| caution |
When measuring the resistance, disconnect the
negative battery
terminal.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN4) terminal Nos.3
and 14.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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YES : <1 kΩ or
more> Go to Step 10.
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<Less than 1
kΩ> Go to Step 9.
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STEP 9. Resistance measurement at camera-ECU connector.
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| caution |
A digital multimeter should be used.
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(1)Remove the camera-ECU, and measure at the equipment
side.
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(2)Resistance between camera-ECU connector terminal Nos.1 and
21.
OK: 1 kΩ or more
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Q.
Is the check result normal?
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<1 kΩ or more>
Repair the wiring harness between joint
connector (CAN4) and the camera-ECU connector.
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<Less than 1 kΩ>
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 10. Resistance measurement at joint connector
(CAN4).
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| caution |
A digital multimeter should be used.
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| caution |
The test wiring harness should be used.
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(1)Disconnect joint connector (CAN4), and measure at the
wiring harness side.
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(2)Turn the ignition switch to the "LOCK" (OFF)
position.
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(3)
| caution |
When measuring the resistance, disconnect the
negative battery
terminal.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN4) terminal Nos.11
and 22.
OK: 120 ± 20 Ω
| caution |
Strictly observe the specified wiring harness repair
procedure.
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Q.
Is the check result normal?
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<Within 120 ± 20
Ω> 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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<Not within 120 ± 20
Ω> Go to Step 11.
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STEP 11. Resistance measurement at A/C-ECU connector.
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| caution |
A digital multimeter should be used.
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(1)Remove the A/C-ECU, and measure at the equipment
side.
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(2)Resistance between A/C-ECU connector terminal Nos.1 and
2.
OK: 120 ± 20 Ω
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Q.
Is the check result normal?
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<Within 120 ± 20
Ω> Repair the wiring harness between
joint connector (CAN4) and the A/C-ECU connector.
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<Not within 120 ± 20
Ω> 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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