Diagnosis Item 22: Diagnose the lines between the joint connectors (CAN3 and CAN1).
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 "diagnose the lines between the joint connectors (CAN3 and CAN1)" when the M.U.T.-III checks the periodically sent data from each ECU and cannot receive the engine-ECU data.
TROUBLE JUDGEMENT CONDITIONS
M.U.T.-III judges the trouble when the periodically sent data from engine-ECU cannot be received.
PROBABLE CAUSE
Damaged harness wires and connectors
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STEP 1. Connector check: C-126 intermediate connector, joint connector (CAN3) and joint connector (CAN1)
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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.
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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 (CAN3) and C-126 intermediate connector.
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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 the joint connector (CAN3) and the intermediate 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.
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Ensure that the negative battery terminal is disconnected.
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(4)Continuity between joint connector (CAN3) terminal No.10 and C-126 intermediate connector terminal No.15 <LHD> OK: Continuity (2 Ω or less)
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(5)Continuity between joint connector (CAN3) terminal No.21 and C-126 intermediate connector terminal No.16 <LHD> OK: Continuity (2 Ω or less)
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(6)Continuity between joint connector (CAN3) terminal No.8 and C-126 intermediate connector terminal No.15 <RHD> OK: Continuity (2 Ω or less)
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(7)Continuity between joint connector (CAN3) terminal No.17 and C-126 intermediate connector terminal No.16 <RHD> OK: Continuity (2 Ω or less)
caution |
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> Go to Step 3.
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NO : <Either or all of the resistances measure more than 2 Ω> Repair the wiring harness between joint connector (CAN3) and intermediate connector C-126.
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STEP 3. Resistance measurement at joint connector (CAN1) and C-126 intermediate connector.
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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 (CAN1) and the intermediate 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.
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Ensure that the negative battery terminal is disconnected.
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(4)Continuity between joint connector (CAN1) terminal No.9 and C-126 intermediate connector terminal No.15 OK: Continuity (2 Ω or less)
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(5)Continuity between joint connector (CAN1) terminal No.18 and C-126 intermediate connector terminal No.16 OK: Continuity (2 Ω or less)
caution |
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> Follow diagnosis item 20, 21, 23, 24, 25, 26, 27, 28 and 29. Refer to .
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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 intermediate connector C-126.
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