Code No.U1000 OSS CAN timeout
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- If diagnosis code No. U1000 is stored in the ETACS-ECU, always diagnose the CAN bus line.
- Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
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DIAGNOSTIC FUNCTION
If the signal from OSS-ECU cannot be received, the ETACS-ECU stores diagnosis code No. U1000.
JUDGEMENT CRITERIA
After the following statuses continue to be true for 5 seconds, if the communication with the OSS-ECU cannot be established for 2,500 ms or more, the ETACS-ECU determines that a problem has occurred.
- No abnormality is present to the network.
- Ignition switch is in the ON position.
- No abnormality is present to the power supply fuse (IOD fuse), or the odometer value is at 80.5 km or more.
- ETACS-ECU system voltage is at 10-16 V.
PROBABLE CAUSES
- Malfunction of the OSS-ECU
- Malfunction of the ETACS-ECU
- Damaged harness wires and connectors
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 line (Refer to GROUP 54C - Troubleshooting 
).
STEP 2. M.U.T.-III other system diagnosis code
Check if diagnosis code is stored in the OSS-ECU.
Q.
Is the diagnosis code stored?
Troubleshoot the OSS. Refer to GROUP 42B - Troubleshooting .
Go to Step 3.
STEP 3. M.U.T.-III other system diagnosis code
Check if diagnosis code No. U1000 is stored in the KOS-ECU.
Q.
Is the diagnosis code stored?
Go to Step 4.
Go to Step 5.
STEP 4. Check whether the diagnosis code is stored again.
Check again if the diagnosis code is stored in the ETACS-ECU.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
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(3)Check if diagnosis code is stored.
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Q.
Is the diagnosis code stored?
Replace the OSS-ECU.
The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the OSS-ECU and the ETACS-ECU (GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
STEP 5. Check whether the diagnosis code is stored again.
Check again if the diagnosis code is stored in the ETACS-ECU.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
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(3)Check if diagnosis code is stored.
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Q.
Is the diagnosis code stored?
Replace the ETACS-ECU.
The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the OSS-ECU and the ETACS-ECU (GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).