If the key certification result by KOS-ECU does not match with the engine-ECU status,
KOS-ECU sets the diagnosis code No. B1A28.
JUDGEMENT CRITERIA
KOS-ECU determines that the abnormality is present, if the key certification result and
the engine ECU’s status do not match after the engine start permission communication
is completed.
PROBABLE CAUSES
Malfunction of KOS-ECU
Engine-ECU malfunction
Chassis number registered in engine-ECU unmatched
DIAGNOSIS PROCEDURE
STEP 1. Check the chassis number registered in the engine-ECU
and the vehicle’s chassis number.
Check if chassis number registered in the engine- ECU matches with the vehicle’s
chassis number.
Q.
Do chassis number registered in the engine-ECU and the vehicle’s chassis
number match?
Go to Step 2.
Replace the engine-ECU and record the chassis number [Refer to GROUP
00 -
How To Perform Chassis Number (Chassis No.) Writing ].
After registering the chassis number, go to Step 2.
STEP 2. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.
(1)Turn the ignition switch from the LOCK (OFF) position to the ON position.
(2)Check if the diagnosis code is set.
Q.
Is the diagnosis code set?
Replace KOS-ECU and register the ID codes (Refer to ).
Intermittent malfunction is suspected (Refer to GROUP 00 -
How to Use Troubleshooting/Inspection
Service Points -
How to Deal with Intermittent Malfunction ).