Diagnosis Item
3: Diagnose shorts between CAN_H and L lines
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 M.U.T.-III judges a short between CAN_H and CAN_L line when all
data from ECU cannot be received while checking periodically sent data from each ECU even if
the voltage is normal.
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 EV-ECU
Malfunction of the inverter
Malfunction of the BMU
Malfunction of the on board charger/DC-DC converter
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.
STEP 2. Resistance measurement at B-24 joint connector (CAN1)
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 connector, and measure at its female-side joint connector (CAN1)
(at the instrument panel wiring harness side).
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between B-24 joint connector (CAN1) terminal Nos.11 and 22 OK: 120 ± 20 Ω
Q.
Is the check result normal?
<Within 120 ± 20 Ω> Go to Step 13.
<Not within 120 ± 20 Ω> Go to Step 3.
STEP 3. Resistance measurement at C-103 joint connector (CAN2).
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 connector, and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between C-103 joint connector (CAN2 terminal Nos.8 and 19 OK: 120 ± 20 Ω
Q.
Is the check result normal?
<Within 120 ± 20 Ω> Go to Step 5.
<Not within 120 ± 20 Ω> Go to Step 4.
STEP 4. Resistance measurement at C-108 EV-ECU connector.
caution
A digital multimeter should be used. For details refer to .
(1)Remove the EV-ECU, and measure at the equipment side.
(2)Resistance between C-108 EV-ECU connector terminal Nos.54 and 55 OK: 120 ± 20 Ω
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<Within 120 ± 20 Ω> Repair the wiring harness
between joint connector (CAN2) and the EV-ECU connector.
<Not within 120 ± 20 Ω> Check the EV-ECU connector,
and repair if necessary. If the EV-ECU connector is in good condition, replace the EV-ECU and
register the ID codes (Refer to GROUP 54A, Immobilizer system - On-vehicles service ).
STEP 5. Resistance measurement at C-103 joint connector (CAN2).
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 connector, and measure at the wiring harness side.
(2)Turn the electric motor 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 auxiliary battery terminal is disconnected.
(4)Resistance between C-103 joint connector (CAN2) terminal Nos.6 and 17 OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Go to Step 7.
<Less than 1 kΩ> Go to Step 6.
STEP 6. Resistance measurement at E-06 inverter connector.
danger
Carry out the check on the high-voltage circuit while reading
carefully the precautions on handling a high-voltage vehicle. Refer to .
danger
Wear the specified protection equipment during the check.
caution
A digital multimeter should be used. For details refer to .
(1)Remove the inverter, and measure at the equipment side.
(2)Resistance between E-06 inverter connector terminal Nos.3 and 8 OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Prior to the wiring harness inspection,
check C-102 intermediate connector, and repair if necessary. Repair the wiring harness between
joint connector (CAN2) and the inverter connector.
<Less than 1 kΩ> Check the inverter connector, and
repair if necessary. If the inverter connector is in good condition, replace the inverter and
register the ID codes (Refer to GROUP 54A, Immobilizer system - On-vehicles service ).
STEP 7. Resistance measurement at C-103 joint connector (CAN2).
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 joint connector (CAN1), and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between C-103 joint connector (CAN2) terminal Nos.9 and 20 OK: 120 ± 20 Ω
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Go to Step 9.
<Less than 1 kΩ> Go to Step 8.
STEP 8. Resistance measurement at C-107 BMU connector.
caution
A digital multimeter should be used. For details refer to .
(1)Remove the BMU, and measure at the equipment side.
(2)Resistance between C-107 BMU connector terminal Nos.6 and 7 OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint
connector (CAN2) and the BMU connector.
<Less than 1 kΩ> Check the BMU connector, and repair
if necessary. If the BMU connector is in good condition, replace the BMU.
STEP 9. Resistance measurement at C-103 joint connector (CAN2).
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 connector, and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between C-103 joint connector (CAN2) terminal Nos.7 and 18 OK: 120 ± 20 Ω
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Go to Step 11.
<Less than 1 kΩ> Go to Step 10.
STEP 10. Resistance measurement at E-03 on board charger/DC-DC
converter.
danger
Carry out the check on the high-voltage circuit while reading
carefully the precautions on handling a high-voltage vehicle. Refer to .
danger
Wear the specified protection equipment during the check.
caution
A digital multimeter should be used. For details refer to .
(1)Remove the on board charger/DC-DC converter, and measure at the equipment
side.
(2)Resistance between E-03 on board charger/DC-DC converter connector terminal Nos.06
and 13 OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Prior to the wiring harness inspection,
check C-102 intermediate connector, and repair if necessary.Repair the wiring harness between
joint connector (CAN2) and the on board charger/DC-DC converter connector connector.
<Less than 1 kΩ> Check the on board charger/DC-DC
converter connector, and repair if necessary. If the on board charger/DC-DC converter
connector is in good condition, replace the on board charger/DC-DC converter.
A digital multimeter should be used. For details refer to .
caution
The test wiring harness should be used. For details refer
to .
(1)Disconnect joint connector (CAN1), and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between C-103 joint connector (CAN1) terminal Nos.10 and 21 OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> The trouble can be an intermittent malfunction
(Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How
to Cope with Intermittent Malfunction ).
<Less than 1 kΩ> Go to Step 12.
STEP 12. Resistance measurement at C-101 A/C control unit.
caution
A digital multimeter should be used. For details refer to .
(1)Remove the compressor/heater controller, and measure at the equipment
side.
(2)Resistance between C-101 A/C control unit connector terminal Nos.03 and 04 OK: 120 ± 20 Ω
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint
connector (CAN2) and the compressor/heater controller connector.
<Less than 1 kΩ> Check the compressor/heater
controller connector, and repair if necessary. If the compressor/heater controller
connector is in good condition, replace the compressor/heater controller.
STEP 13. Resistance measurement at B-24 joint connector (CAN1).
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 connector, and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between B-24 joint connector (CAN1) terminal Nos.7 and 18 <LHD> OK: 1 kΩ or more
(5)Resistance between B-24 joint connector (CAN1) terminal Nos.6 and 17 <RHD> OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<Within 120 ± 20 Ω> Go to Step 15.
<Not within 120 ± 20 Ω> Go to Step 14.
STEP 14. Resistance measurement at B-317 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 B-317 ETACS-ECU connector terminal Nos.56 and 65 OK: 120 ± 20 Ω
Q.
Is the check result normal?
<Within 120 ± 20 Ω> Repair
the wiring harness between joint connector (CAN1) and the ETACS-ECU connector.
<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 and register the ID codes (Refer to GROUP 54A, Immobilizer system - On-vehicles
service ).
STEP 15. Resistance measurement at B-24 joint connector (CAN1).
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 joint connector (CAN1), and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between B-24 joint connector (CAN1) terminal Nos.6 and 17 <LHD> OK: 1 kΩ or more
(5)Resistance between B-24 joint connector (CAN1) terminal Nos.5 and 16 <RHD> OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Go to Step 17.
<Less than 1 kΩ> Go to Step 16.
STEP 16. Resistance measurement at B-101 combination meter connector.
caution
A digital multimeter should be used. For details refer to .
(1)Remove the combination meter, and measure at the equipment side.
(2)Resistance at B-101 combination meter connector terminal Nos.17 and 18 OK: 1 kΩ or more
Q.
Is the check result normal?
<1 kΩ or more> Prior to the wiring harness inspection,
check B-120 intermediate connector, and repair if necessary. Repair the wiring harness between
joint connector (CAN1) and the combination meter connector.
<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.
STEP 17. Resistance measurement at B-24 joint connector (CAN1).
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 joint connector (CAN1), and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliarybattery terminal is disconnected.
(4)Resistance between B-24 joint connector (CAN1) terminal Nos.9 and 20 OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Go to Step 19.
NO : <Less than 1 kΩ> Go to Step 18.
STEP 18. Resistance measurement at A-14 ASC-ECU connector.
caution
A digital multimeter should be used. For details refer to .
(1)Connect special tool MB991951 to the ASC-ECU connector, and measure by using the check
connector (connect the ECU side only).
(2)Measure the resistance between special tool MB991951 check connector terminal Nos. 14
and 26. OK: 1 kΩ or more
Q.
Is the check result normal?
<1 kΩ or more> Prior to the wiring harness inspection,
check B-01 intermediate connector, and repair if necessary.Repair the wiring harness between
joint connector (CAN1) and the ASC-ECU connector.
<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.
STEP 19. Resistance measurement at B-24 joint connector (CAN1).
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 joint connector (CAN1), and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
(4)Resistance between B-24 joint connector (CAN1) terminal Nos.8 and 19 OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Go to Step 21.
<Less than 1 kΩ> Go to Step 20.
STEP 20. Resistance measurement at B-114 EPS-ECU connector.
caution
A digital multimeter should be used. For details refer to .
(1)Remove the EPS-ECU, and measure at the equipment side.
(2)Resistance at B-114 EPS-ECU connector terminal Nos.5 and 6 OK: 1 kΩ or more
Q.
Is the check result normal?
<1 kΩ or more> Prior to the wiring harness inspection,
check B-27 intermediate connector, and repair if necessary. Repair the wiring harness between
joint connector (CAN1) and the EPS-ECU connector.
<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.
STEP 21. Resistance measurement at B-24 joint connector (CAN1).
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 joint connector (CAN1), and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between B-24 joint connector (CAN1) terminal Nos.5 and 16 <LHD> OK: 1 kΩ or more
(5)Resistance between B-24 joint connector (CAN1) terminal Nos.4 and 15 <RHD> OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Go to Step 23.
NO : <Less than 1 kΩ> Go to Step 22.
STEP 22. Resistance measurement at B-204 steering wheel sensor connector.
caution
A digital multimeter should be used. For details refer to .
(1)Remove the steering wheel sensor, and measure at the equipment side.
(2)Resistance at B-204 steering wheel sensor connector terminal Nos.3 and 4 OK: 1 kΩ or more
Q.
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint
connector (CAN2) and the steering wheel sensor connector.
<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.
STEP 23. Resistance measurement at B-24 joint connector (CAN1).
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 joint connector (CAN1), and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between B-24 joint connector (CAN1) terminal Nos.4 and 15 <LHD> OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
(5)Resistance between B-24 joint connector (CAN1) terminal Nos.3 and 14 <RHD> OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> Go to Step 25.
<Less than 1 kΩ> Go to Step 24.
STEP 24. Resistance measurement at C-20 G and yaw rate sensor connector.
caution
A digital multimeter should be used. For details refer to .
(1)Remove the G and yaw rate sensor, and measure at the equipment side.
(2)Resistance at C-20 G and yaw rate sensor connector terminal Nos.2 and 3 OK: 1 kΩ or more
Q.
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint
connector (CAN1) and the G and yaw rate sensor connector.
<Less than 1 kΩ> Check the G and yaw rate sensor connector,
and repair if necessary. If the G and yaw rate sensor connector is in good condition, replace
the G and yaw rate sensor.
STEP 25. Resistance measurement at B-24 joint connector (CAN1).
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 joint connector (CAN1), and measure at the wiring harness side.
(2)Turn the electric motor switch to the LOCK (OFF) position.
(3)
caution
When measuring the resistance, disconnect the negative auxiliary
battery terminal. For details refer to .
Ensure that the negative auxiliary battery terminal is disconnected.
(4)Resistance between B-24 joint connector (CAN1) terminal Nos.10 and 21 OK: 1 kΩ or more
caution
Strictly observe the specified wiring harness repair procedure.
For details refer to .
Q.
Is the check result normal?
<1 kΩ or more> The trouble can be an intermittent malfunction
(Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How
to Cope with Intermittent Malfunction ).
<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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Go to Step 2
Repair the defective connector.)
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: <Less than 1 kΩ> Go to Step 18.)
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