Code No. U1122: Failure information on ABS-ECU or TCL/ASC-ECU
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- If diagnosis code No. U1122 is set in the combination meter, always diagnose the CAN bus lines.
- Whenever the ECU is replaced, ensure that the input and output signal circuits are normal.
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TROUBLE JUDGMENT
The combination meter communicates with the ABS-ECU or TCL/ASC-ECU through CAN bus lines. If failure information is sent from the ABS or the TCL/ASC-related signal, diagnosis code No. U1122 will be set.
COMMENT ON TROUBLE SYMPTOM
The M.U.T.-III shows a diagnosis code status as active.
- The wiring harness wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, the ABS-ECU or the TCL/ASC-ECU may be defective.
The M.U.T.-III shows a diagnosis code status as stored.
- If diagnosis code No.U1122 is stored as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) between the ABS-ECU or the TCL/ASC-ECU and the combination meter. For diagnosis procedures, refer to "How to treat past trouble" (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points
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PROBABLE CAUSES
- Malfunction of the ABS-ECU or the TCL/ASC-ECU
- Malfunction of the combination meter
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnostics
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Since the radiator fan rotates during CAN bus line diagnostics, make sure that no one is servicing the engine compartment before diagnosing the CAN bus line. Since the CAN communication stops when diagnosing the CAN bus line, the ETACS-ECU detects the time-out of the engine-ECU, and activates the radiator fan to prevent overheating as fail-safe.
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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 ). Repair the CAN bus line and go to Step 5.
STEP 2. M.U.T.-III other system diagnosis code
Check that the ABS-ECU or the TCL/ASC-ECU sets a diagnosis code.
Q.
Is the diagnosis code set?
Diagnose the ABS-ECU or the TCL/ASC-ECU (Refer to GROUP 35B, Troubleshooting or GROUP 35C, Troubleshooting ). And then go to Step 3.
Go to Step 3.
STEP 3. M.U.T.-III other system diagnosis code
Check if a diagnosis code, which relates to CAN communication-linked systems below, is set.
Electric power steering-ECU
- Code No. U1122: Failure information on ABS-ECU or TCL/ASC-ECU
Q.
Is the diagnosis code set?
Go to Step 5.
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)Ignition switch: "LOCK" (OFF) position 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 diagnosis code set?
After the combination meter is replaced, then perform the variant coding and write the VIN data (Refer to GROUP 00, Precautions Before Service - How to Perform Variant Coding ). Then go to Step 5.
A poor connection, open circuit or other intermittent malfunction between the ABS-ECU or the TCL/ASC-ECU and the allshift lever (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points ).
STEP 5. 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)Ignition switch: "LOCK" (OFF) position 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 diagnosis code set?
Return to Step 1.
The procedure is complete.