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Diagnosis code 31: Open circuit in signal line between the SRS-ECU and the ETACS-ECU (impact detection signal)
Diagnosis code 32: Short circuit in signal line between the SRS-ECU and the ETACS-ECU (impact detection signal)
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|  CAUTION
Whenever the ECU is replaced, ensure that the input signal circuit is normal.
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| COMMENTS ON TROUBLE SYMPTOM
If the voltage in the signal line between the SRS-ECU and the ETACS-ECU has exceeded 4.6 V for 40 milliseconds or more, the ETACS-ECU will set diagnosis code No.31 as an open circuit. If the signal line voltage has reached 1.5 V or less for at least 2.5 seconds, the ETACS-ECU will set diagnosis code No.32 as a short circuit. If the ignition switch is turned off, the ETACS-ECU will stop sending the diagnosis code.
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| POSSIBLE CAUSES
- Malfunction of the SRS-ECU
- Malfunction of the ETACS-ECU
- Damaged harness wires and connectors
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| Step 1. Use the MUT-II/III to confirm a diagnosis code. (MUT-II/III diagnosis code)
Check that the SRS-ECU sets a diagnosis code.
Q: Is the check result normal?
YES:
Go to Step 2  .
NO:
Refer to GROUP 52B -
Troubleshooting  .
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| Step 2. Connector check: C-115 SRS-ECU connector and C-220 ETACS-ECU connector Q: Is the check result normal?
YES:
Go to Step 3 .
NO:
Repair the defective connector.
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| Step 3. Measure the resistance at the C-115 SRS-ECU connector. - Disconnect the connector, and measure at the wiring harness side.
- Resistance between C-115 SRS-ECU connector terminal No.15 and body earth
OK: 2 Ω
or less
Q: Is the check result normal?
YES:
Go to Step 5 .
NO:
Go to Step 4 .
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| Step 4. Check the wiring harness between C-115 SRS-ECU connector terminal No.15 and body earth. - Check the earth wires for open circuit.
Q: Is the check result normal?
YES:
The trouble can be an intermittent malfunction (Refer to GROUP 00 -
How to Cope with Intermittent Malfunction ).
NO:
Repair the wiring harness.
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| Step 5. Check the wiring harness between C-220 SRS-ECU connector terminal No.29 and C-115 SRS-ECU connector terminal No.14. - Check the communication lines for open circuit.
Q: Is the check result normal?
YES:
Go to Step 6 .
NO:
Repair the wiring harness.
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| Step 6. Check whether the diagnosis code is reset.
Replace the ETACS-ECU, and then check that the diagnosis code is not reset.
- Replace the ETACS-ECU.
- Ignition switch: ON
- Check that diagnosis code No.31 or 32 is not reset.
Q: Is diagnosis code No.31 or 32 set?
YES:
Replace the SRS-ECU.
NO:
The procedure is complete.
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