Diagnosis Item
16: Diagnose when the M.U.T.-III cannot receive the data sent by clearance warning control unit. <Vehicles
with ultrasonic misacceleration mitigation, blind spot warning or corner sensor system for LHD>
| 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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FUNCTION
The diagnostic result demonstrates that "the M.U.T.-III cannot receive the sent data from
the combination meter" when the M.U.T.-III checks the periodically sent data from each ECU and
cannot receive the combination meter data only.
TROUBLE JUDGEMENT CONDITIONS
M.U.T.-III judges the trouble when the periodically sent data from combination meter cannot
be received.
PROBABLE CAUSES
- Damaged harness wires and connectors
- Power supply circuit malfunction of the combination meter
- Malfunction of the clearance warning control unit
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STEP 1. Connector check: joint connector (CAN1) and clearance
warning control unit connector
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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.
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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. Replace the joint connector as necessary.
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STEP 2. Resistance measurement at joint connector (CAN1) and clearance
warning control unit connector.
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A digital multimeter should be used.
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The test wiring harness should be used.
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(1)Disconnect joint connector (CAN1) and the combination meter 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)
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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)Continuity between joint connector (CAN1) terminal No.6 and clearance warning control
unit connector terminal No.4.
OK: Continuity (2 Ω or less)
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(5)Continuity between joint connector (CAN1) terminal No.17 and clearance warning
control unit connector terminal No.3.
OK: Continuity (2 Ω or less)
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Strictly observe the specified wiring harness repair procedure.
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Q.
Is the check result normal?
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<All the resistances measure 2 Ω or less> Power supply
to the clearance warning control unit may be suspected. Diagnose the clearance warning control unit
(Refer to GROUP 54A - Unintended Acceleration mitigation System/BSW/Corner Sensor System, Clearance
Warning Control unit, Troubleshooting).
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NO : <Either or all of the resistances measure more than 2 Ω> Repair
the wiring harness between joint connector (CAN1) and the clearance warning control unit.
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