If diagnosis code No. B1A28 is set, diagnose the CAN bus lines.
When replacing the ECU, always check that the communication circuit is normal.
DIAGNOSTIC FUNCTION
When the KOS&OSS-ECU certification result is different from the engine status after the completion of engine starting permission communication, KOS&OSS-ECU determines that a problem has occurred, and sets diagnosis code No.B1A28. At the same time, KOS&OSS-ECU displays the immobilizer certification system inspection warning to the combination meter.
JUDGEMENT CRITERIA
Check Conditions
At engine starting certification
Judgement Criterion
Certification result unmatch is received from engine-ECU.
PROBABLE CAUSES
Writing error of chassis number to engine-ECU (engine-ECU has been interchanged between two vehicles, or chassis number has not been written after engine-ECU replacement)
Malfunction of the CAN bus line
Malfunction of KOS&OSS-ECU
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 diagnosis code
Check if KOS&OSS-ECU diagnosis code No.B1161 is set.
Q.
Is the diagnosis code set?
Troubleshoot for the relevant diagnosis code (Refer to ).
Go to Step 3.
STEP 3. M.U.T.-III other system diagnosis code
(1)Check that the vehicle power can be turned ON and engine is started.
(2)Check the diagnosis code of engine-ECU.
Q.
Is the diagnosis code set?
Troubleshoot the engine-ECU (Refer to GROUP 13B - Troubleshooting <6B3> or GROUP 13C - Troubleshooting <4N1>). Then go to Step 4.
Go to Step 4.
STEP 4. Check whether the diagnosis code is set again.
(1)Operate the engine switch several times within five seconds without depressing the brake pedal to turn on and off the power supply mode.
(2)Check again if the diagnosis code is set in the KOS&OSS-ECU.
Q.
Is the diagnosis code set?
Replace the KOS&OSS-ECU and register the chassis number (Refer to ). Then go to Step 5.
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
STEP 5. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set in the KOS&OSS-ECU.
Q.
Is the diagnosis code set?
Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU <6B3> or GROUP 13C - Engine-ECU <4N1>).