[ Model - ECLIPSE CROSS / Year - 2018 ]
2018 / ECLIPSE CROSS / EC - Workshop Manual
54 -CHASSIS ELECTRICAL > 54A-CHASSIS ELECTRICAL > IMMOBILIZER SYSTEM<Vehicles without keyless operation system><Vehicles without keyless operation system> > DIAGNOSIS CODE PROCEDURES > B1731 ENG ECU authentication timeout
Code No.B1731 ENG ECU authentication timeout
 
 
caution
  • When diagnosis code No. B1731 is set, be sure to diagnose the CAN bus line.
  • When replacing the ECU, always check that the communication circuit is normal.
 
 
DIAGNOSIS FUNCTION
ETACS-ECU checks if the data from the engine-ECU is received via the CAN bus line. When ETACS-ECU cannot receive the engine-ECU data, it sets diagnosis code No. B1731.
 
 
JUDGEMENT CRITERIA
ETACS-ECU determines that the abnormality is present, if it cannot receive the data from the engine-ECU via the CAN bus line when the ignition switch is turned "ON".
 
 
PROBABLE CAUSES
  • Malfunction of CAN bus line
  • Damaged wiring harness and connectors
  • Malfunction of Engine-ECU
  • Malfunction of ETACS-ECU
 
 
DIAGNOSIS PROCEDURE
STEP 1. Check whether the diagnosis code is set again.
Recheck if the diagnosis code is set in the ETACS-ECU.
(1) Erase the diagnosis code.
(2) Remove the ignition key from key cylinder and insert it again then turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3) On completion, check that the diagnosis code is not set again.
Is the diagnosis code set?
Go to Step 2.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 2. M.U.T.-IIISE CAN bus diagnostics
Use M.U.T.-IIISE to diagnose the CAN bus lines.
Is the check result normal?
Go to Step 3.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 3.
 
STEP 3. M.U.T.-IIISE other system diagnosis code
Check whether an engine-related diagnosis code is set.
Is the diagnosis code set?
Perform troubleshooting for the engine (Refer to GROUP 13A - Troubleshooting ).
Go to Step 4.
 
STEP 4. M.U.T.-IIISE other system diagnosis code
Check if diagnosis code No.U0100 is set in ETACS-ECU.
Is the diagnosis code set?
Go to Step 6.
Go to Step 5.
 
STEP 5. Check whether the diagnosis code is set again.
Recheck if the diagnosis code is set in the ETACS-ECU.
(1) Remove the ignition key from key cylinder and insert it again then turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(2) Check if the diagnosis code is set.
Is the diagnosis code set?
Replace ETACS-ECU (Refer to ) and register the ID codes (Refer to ).
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
 
STEP 6. Check whether the diagnosis code is set again.
Recheck if the diagnosis code is set in the ETACS-ECU.
(1) Remove the ignition key from key cylinder and insert it again then turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(2) Check if the diagnosis code is set.
Is the diagnosis code set?
Replace the engine-ECU and register the chassis number and key codes [Refer to GROUP 00 - How to Perform Chassis Number (Chassis No.) Writing ].
The diagnosis is complete.