Diagnosis Item
4: Diagnose shorts between CAN_H and L lines. <Vehicles for
GCC>
| 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 bus lines (CAN_L and CAN_H lines) is
1.0
V or more, 4.0 V or less.
- The resistance at CAN 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 ETACS-ECU
- Malfunction of the combination meter
- Malfunction of the SRS-ECU
- Malfunction of the EPS-ECU
- Malfunction of the ASC-ECU
- Malfunction of the steering wheel sensor
- Malfunction of the CVT-ECU
- Malfunction of the engine-ECU
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STEP 1. Connector check: C-213 intermediate connector.
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| caution |
The strand end of the twist wire should be within
10 cm from
the connector. For details refer to service precautions.
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Q.
Is the check result normal?
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 Go to Step 2.
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 Repair
the defective connector.
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STEP 2. Resistance measurement at C-213 intermediate
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.
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(1)Disconnect the connector, and measure at its female-side
intermediate connector
(at the front 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between C-213 intermediate 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>
Go to Step 12.
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<Not within 120 ±
20 Ω>
Go to Step 3.
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STEP 3. Connector check: joint connector (CAN2).
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| caution |
The strand end of the twist wire should be within
10 cm from
the connector. For details refer to service precautions.
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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 4.
Repair a defective connector or
replace the joint connector.
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STEP 4. Resistance measurement at joint connector (CAN2).
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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.
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(1)Disconnect the connector, 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN2) terminal Nos. 11
and 22.
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 6.
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NO : <Not within 120 ±
20 Ω>
Go to Step 5.
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STEP 5. Resistance measurement at engine-ECU connector.
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| caution |
- A digital multimeter should
be used. 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)Remove the engine-ECU, and measure at the equipment
side.
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(2)Resistance between engine-ECU connector terminal Nos. 71
and 72.
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 (CAN2) and the engine-ECU connector.
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<Not within 120 ±
20 Ω>
Check the engine-ECU connector,
and repair if necessary. If the engine-ECU connector is in good condition,
replace the engine-ECU.
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STEP 6. Resistance measurement at joint connector (CAN2).
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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.
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(1)Disconnect the connector, 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN2) terminal Nos. 7
and 18.
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 8.
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<Less than 1
kΩ>
Go to Step 7.
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STEP 7. Resistance measurement at CVT-ECU connector.
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| caution |
- A digital multimeter should
be used. 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)Remove the CVT-ECU, and measure at the equipment
side.
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(2)Resistance between CVT-ECU connector terminal Nos. 9 and
10.
OK: 1 kΩ
or more
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Q.
Is the check result normal?
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<1 kΩ
or more>
Check intermediate connector, and repair
if necessary. If the intermediate connector is in good condition, repair
the wiring harness
between joint connector (CAN2) and the CVT-ECU connector.
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<Less than 1 kΩ>
Check the CVT-ECU connector, and repair
if necessary. If the CVT-ECU connector is in good condition, replace the
CVT-ECU.
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STEP 8. Resistance measurement at joint connector (CAN2).
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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.
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(1)Disconnect the connector, 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN2) terminal Nos. 9
and 20.
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 10.
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<Less than 1
kΩ>
Go to Step 9.
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STEP 9. Resistance measurement at ASC-ECU connector.
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| caution |
- A digital multimeter should
be used. 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)Remove the ASC-ECU, and measure at the equipment
side.
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(2)Resistance between ASC-ECU connector terminal Nos. 26 and
14.
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 (CAN2) and the ASC-ECU.
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<Less than 1 kΩ>
Check the ASC-ECU connector, and repair
if necessary. If the ASC-ECU connector is in good condition, replace the
ASC-ECU. (Refer to GROUP
35C -
Hydraulic Unit  ).
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STEP 10. Resistance measurement at joint connector
(CAN2).
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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.
- Strictly observe the specified wiring harness repair procedure. For
details refer
to service precautions.
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(1)Disconnect the connector, 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN2) terminal Nos. 8
and 19.
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 (CAN2) and C-213 intermediate connector.
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<Less than 1
kΩ>
Go to Step 11.
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STEP 11. Resistance measurement at EPS-ECU connector.
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| caution |
- A digital multimeter should
be used. 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)Remove the EPS-ECU, and measure at the equipment
side.
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(2)Resistance between EPS-ECU connector terminal Nos. 3 and
4.
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 (CAN2) and the EPS-ECU connector.
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<Less than 1 kΩ>
Check the EPS-ECU connector, and repair
if necessary. If the EPS-ECU connector is in good condition, replace the
EPS-ECU.
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STEP 12. Connector check: joint connector (CAN1).
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| caution |
The strand end of the twist wire should be within
10 cm from
the connector. For details refer to service precautions.
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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 13.
Repair a defective connector or
replace the joint connector.
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STEP 13. Resistance measurement at joint connector
(CAN1).
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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.
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(1)Disconnect joint connector (CAN1), 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN1) 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 15.
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NO : <Not within 120 ±
20 Ω>
Go to Step 14.
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STEP 14. Resistance measurement at ETACS-ECU connector.
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| caution |
- A digital multimeter should
be used. 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)Remove the ETACS-ECU, and measure at the equipment
side.
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(2)Resistance at ETACS-ECU connector terminal Nos. 56 and
65.
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 (CAN1) and the ETACS-ECU connector.
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<Not within 120 ±
20 Ω>
Check the ETACS-ECU connector,
and repair if necessary. If the ETACS-ECU connector is in good condition,
replace the ETACS-ECU.
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STEP 15. Resistance measurement at joint connector
(CAN1).
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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.
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(1)Disconnect joint connector (CAN1), 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN1) terminal Nos. 6
and 17.
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 17.
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<Less than 1
kΩ>
Go to Step 16.
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STEP 16. Resistance measurement at combination meter
connector.
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| caution |
- A digital multimeter should
be used. 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)Remove the combination meter, and measure at the equipment
side.
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(2)Resistance at combination meter connector terminal Nos. 14
and 15.
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 (CAN1) and the combination meter connector.
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<Less than 1 kΩ>
Check the combination meter connector,
and repair if necessary. If the combination meter connector is in good
condition, replace the combination
meter.
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STEP 17. Resistance measurement at joint connector
(CAN1).
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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.
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(1)Disconnect joint connector (CAN1), 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN1) terminal Nos. 4
and 15.
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 19.
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<Less than 1
kΩ>
Go to Step 18.
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STEP 18. Resistance measurement at SRS-ECU connector.
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| caution |
- A digital multimeter should
be used. 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)Remove the SRS-ECU, and measure at the equipment
side.
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(2)Resistance at SRS-ECU connector terminal Nos. 33 and
34.
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 (CAN1) and the SRS-ECU connector.
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<Less than 1 kΩ>
Check the SRS-ECU connector, and repair
if necessary. If the SRS-ECU connector is in good condition, replace the
SRS-ECU.
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STEP 19. Resistance measurement at joint connector
(CAN1).
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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.
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(1)Disconnect joint connector (CAN1), 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN1) terminal Nos. 3
and 14.
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 21.
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<Less than 1
kΩ>
Go to Step 20.
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STEP 20. Resistance measurement at steering wheel sensor
connector.
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| caution |
- A digital multimeter should
be used. 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)Remove the steering wheel sensor and measure at the
equipment side.
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(2)Resistance at steering wheel sensor connector terminal
Nos. 3 and 4.
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 (CAN1) and the steering wheel sensor connector.
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<Less than 1 kΩ>
Check the steering wheel sensor connector,
and repair if necessary. If the steering wheel sensor connector is in good
condition, replace the
steering wheel sensor. (Refer to GROUP 35C -
Steering Wheel Sensor ).
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STEP 21. Resistance measurement at joint connector
(CAN1).
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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.
- Strictly observe the specified wiring harness repair procedure. For
details refer
to service precautions.
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(1)Disconnect the joint connector (CAN1), 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. For details refer to service precautions.
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Ensure that the negative battery terminal is disconnected.
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(4)Resistance between joint connector (CAN1) terminal Nos. 8
and 19.
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 (CAN1) and the C-213 intermediate connector.
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<Less than 1 kΩ>
Check the diagnosis connector, and
repair if necessary. If the diagnosis connector is in good condition,
repair the wiring harness
between joint connector (CAN1) and the diagnosis connector.
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