Diagnosis Item 11: Diagnose when the M.U.T.-III cannot receive the data
sent by SRS-ECU.
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 SRS-ECU" when the
M.U.T.-III checks the periodically sent data from each ECU and cannot receive
the SRS-ECU data only.
TROUBLE JUDGEMENT CONDITIONS
M.U.T.-III judges the trouble when
the periodically sent data from SRS-ECU cannot be received and sent.
PROBABLE CAUSES
- Damaged harness wires and connectors
- Power supply circuit malfunction of the SRS-ECU
- Malfunction of the SRS-ECU
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STEP 1. Connector check: D-22 joint connector (CAN2) and D-24 SRS-ECU
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 .
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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 D-22 joint connector (CAN2) and D-24
SRS-ECU connector.
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caution |
A digital multimeter should be used. For details
refer to .
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caution |
The test wiring harness should be used. For details
refer to .
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(1)Disconnect joint connector (CAN2) and the SRS-ECU
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 .
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Ensure that the negative battery terminal is disconnected.
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(4)Continuity between D-22 joint connector (CAN2) terminal
No.3 and D-24 SRS-ECU connector terminal No.32 OK: Continuity
(2 Ω or less)
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(5)Continuity between D-22 joint connector (CAN2) terminal
No.9 and D-24 SRS-ECU connector terminal No.43 OK: Continuity
(2 Ω or less)
caution |
Strictly observe the specified wiring harness repair
procedure. For details refer to .
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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 SRS-ECU may be suspected.
Diagnose the SRS-ECU. Refer to .
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NO : <Either or all of the resistances
measure more than 2 Ω> Check the intermediate connector D-231,
and repair if necessary. If the intermediate connector is normal, repair
the wiring harness between joint connector (CAN2) and the SRS-ECU
connector.
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