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DTC B1A08: Keyless/KOS key1 performance
DTC B1A09: Keyless/KOS key2 performance
DTC B1A0A: Keyless/KOS key3 performance
DTC B1A0B: Keyless/KOS key4 performance
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
DTC SET CONDITION
The mechanism which automatically changes a code for lock/unlock each time a lock operation is performed is referred to as a rolling code. If KOS-ECU receives wrong signal (out of synchronization of a rolling code) from the keyless operation key, KOS-ECU memorizes DTC B1A08, B1A09, B1A0A or B1A0B.
 
 
TECHNICAL DESCRIPTION (COMMENT)
  • B1A08: If the difference between the rolling code for the keyless operation key 1 (the first keyless operation key registered with KOS-ECU) and that memorized by KOS-ECU is large, it is judged as abnormal.
  • B1A09: If the difference between the rolling code for the keyless operation key 2 (the second keyless operation key registered with KOS-ECU) and that memorized by KOS-ECU is large, it is judged as abnormal.
  • B1A0A: If the difference between the rolling code for the keyless operation key 3 (the third keyless operation key registered with KOS-ECU) and that memorized by KOS-ECU is large, it is judged as abnormal.
  • B1A0B: If the difference between the rolling code for the keyless operation key 4 (the fourth keyless operation key registered with KOS-ECU) and that memorized by KOS-ECU is large, it is judged as abnormal.
 
 
TROUBLESHOOTING HINTS
  • Rolling code out of synchronization
  • Malfunction of the keyless operation key
  • Malfunction of the KOS-ECU
 
 
DIAGNOSIS
STEP 1. Synchronize the rolling code and recheck the diagnostic trouble code.
Synchronize the rolling codes, and check whether the DTC is reset.
(1) Synchronize the rolling code.
  • Push the lock button or unlock button of keyless operation key twice or more.
  • If the keyless operation does not resume by the procedure above, register the key again (Refer to ).
(2) Recheck if the diagnostic trouble code is set.
(1) Push the lock button or unlock button of keyless operation key.
(2) Check if the diagnostic trouble code is set.
Is the DTC set?
Go to Step 2.
The diagnosis is complete.
 
STEP 2. Check whether the diagnostic trouble code is reset.
Replace the keyless operation key by which the diagnostic trouble code is set with a new one, register the key (Refer to ), and recheck if the diagnostic trouble code is set.
(1) Push the lock button or unlock button of keyless operation key.
(2) Check if the diagnostic trouble code is set.
Is the DTC set?
Replace KOS-ECU and register the ID codes (Refer to ).
The diagnosis is complete.