[ Model - ECLIPSE CROSS / Year - 2018 ]
2018 / ECLIPSE CROSS / EC - Workshop Manual
13 -FUEL > 13A-DIRECT INJECTION AND MULTIPOINT FUEL INJECTION (DI AND MPI) > TROUBLESHOOTING > DIAGNOSIS CODE PROCEDURES > CODE NO. U0121 ASC-ECU TIME-OUT
Code No. U0121: ASC-ECU Time-out
 
 
cautionIf diagnosis code U0121 is set in the engine-ECU, surely perform CAN bus line diagnosis.
cautionReplace ECU after certainly confirming that the communication circuits are normal.
 
 
TROUBLE JUDGEMENT
Check Conditions
  • After 2 seconds have passed since the ignition switch was turned to "ON" position.
  • Battery positive voltage is more than 10 V and is less than 16.5 V.
Judgement Criterion
  • Unable to receive ASC-ECU signals through the CAN bus line for 4 seconds.
 
 
COMMENTS ON TROUBLE SYMPTOM
Current malfunction
  • The failure is possibly caused by malfunction of the harness and connector in CAN bus line between engine-ECU and ASC-ECU, by malfunction in the power supply system of ASC-ECU, in ASC-ECU itself, in engine-ECU.
Past malfunction
  • Proceed with troubleshooting focusing on malfunction of the harness and connector in CAN bus line between engine-ECU and ASC-ECU and malfunction in the power supply system of ASC-ECU. For diagnosis procedure, refer to how to cope with past malfunctions. (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Treat Past Trouble ).
    noteIn the case of past malfunctions, M.U.T.-IIISE CAN bus line diagnosis cannot detect a malfunction even if there is a malfunction in CAN bus. Therefore, check CAN bus line as in the case of response to intermittent malfunctions (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ). It is possible to narrow down areas with a high possibility of malfunctions from diagnosis codes set in each ECU that performs CAN communication (Refer to GROUP 54C - Explanation about the M.U.T.-IIISE CAN Bus Diagnostics ).
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • None
 
 
PROBABLE CAUSES
  • Failed harness and connector
  • Failed ASC-ECU
  • Failed engine-ECU
 
 
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-IIISE CAN bus diagnosis
  • Use M.U.T.-IIISE to perform CAN bus line diagnosis.
Is the check result normal?
Go to Step 2.
Repair CAN bus line (Refer to GROUP 54C - Troubleshooting - CAN Bus Diagnosis Table ). After repairing CAN bus line, go to Step 6.
 
STEP 2. M.U.T.-IIISE diagnosis code
  • Confirm whether the diagnosis code is set in the ASC-ECU.
Is the diagnosis code set?
Perform troubleshooting of the active stability control (ASC) system (Refer to GROUP 35C - Troubleshooting - Diagnosis Code Chart ).
Go to Step 3.
 
STEP 3. M.U.T.-IIISE diagnosis code
Check that the other ECU performing CAN communication with ASC-ECU sets diagnosis code No. U0121 [Refer to GROUP 54C - CAN-related Diagnosis Code Table ].
Is the diagnosis code set?
Go to Step 4.
Go to Step 5.
 
STEP 4. M.U.T.-IIISE diagnosis code
  • Reconfirmation of diagnosis code.
Confirm again whether the diagnosis code is set in the engine-ECU.
  1. Erase the set diagnosis code.
  2. Ignition switch: LOCK (OFF) → ON
  3. Confirm whether the diagnosis code is set.
Is the diagnosis code set?
After replacing ASC-ECU, go to Step 6.
Intermittent malfunction in CAN bus line between engine-ECU and ASC-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
 
STEP 5. M.U.T.-IIISE diagnosis code
  • Reconfirmation of diagnosis code.
Confirm again whether the diagnosis code is set in the engine-ECU.
  1. Erase the set diagnosis code.
  2. Ignition switch: LOCK (OFF) → ON
  3. Confirm whether the diagnosis code is set.
Is the diagnosis code set?
After replacing engine-ECU, go to Step 6.
Intermittent malfunction in CAN bus line between engine-ECU and ASC-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
 
STEP 6. M.U.T.-IIISE diagnosis code
  • Reconfirmation of diagnosis code.
Confirm again whether the diagnosis code is set in the engine-ECU.
  1. Erase the set diagnosis code.
  2. Ignition switch: LOCK (OFF) → ON
  3. Confirm whether the diagnosis code is set.
Is the diagnosis code set?
Go to Step 1.
Check end.