Code No.U1112: SRS-ECU Time-out
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- If diagnosis code U1112 is set in the combination meter, always diagnose the CAN bus lines.
- Whenever the ECU is replaced, ensure that the communication circuit is normal.
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TROUBLE JUDGMENT
The combination meter communicates with the SRS-ECU through CAN bus lines. If it cannot receive all the necessary signals from the SRS-ECU, diagnosis code U1112 is set.
COMMENTS ON TROUBLE SYMPTOM
Current trouble
- Connector(s) or wiring harness in the CAN bus lines between the SRS-ECU and the combination meter, the power supply system to the SRS-ECU, the SRS-ECU itself, or the combination meter may be defective.
Past trouble
- Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the SRS-ECU and the combination meter, and the power supply system to the SRS-ECU. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points
).
| note |
For a past trouble, you may not find it by the M.U.T.-III CAN bus diagnostics even if there is any failure in CAN bus lines. In this case, refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points . and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the diagnosis code, which is set regarding the CAN communication-linked ECUs (Refer to GROUP 54D - CAN Bus Line Diagnostic Flow ).
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PROBABLE CAUSES
- Damaged harness wires and connectors
- Malfunction of SRS-ECU
- Malfunction of combination meter
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.
Q.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54D - Troubleshooting). Repair the CAN bus line and go to Step 4.
STEP 2. M.U.T.-III other system diagnosis code
Check that the SRS-ECU sets a diagnosis code.
Q.
Is the diagnosis code set?
Diagnose the SRS (refer to GROUP 52B - Troubleshooting ).
Go to Step 3.
STEP 3. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch to "ON" position.
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(3)On completion, check that the diagnosis code is not reset.
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Q.
Is the check result normal?
A poor connection, open circuit or other intermittent malfunction is present in the lines between the SRS-ECU and the combination meter (Refer to GROUP 00 - How to use troubleshooting/Inspection Service Points ).
Replace SRS-ECU and then go to step 4.
STEP 4. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch to "ON" position.
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(3)On completion, check that the diagnosis code is not reset.
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Q.
Is the check result normal?
The procedure is complete.
Go to Step 1.