Keyless Operation System (KOS)

DTC B1A08: Keyless/KOS Key1 Performance
DTC B1A09: Keyless/KOS Key2 Performance
DTC B1A0A: Keyless/KOS Key3 Performance
DTC B1A0B: Keyless/KOS Key4 Performance

CAUTION: When 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.

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 key-less 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. Erase the DTC.
2. Turn the ignition switch from the LOCK (OFF) position to the ON position.
3. Press the lock or unlock switch of the keyless operation key for which the diagnosis code is set at least once to synchronize the rolling codes.
4. Check if the DTC is set.

Q: Is the DTC set?

YES : Go to Step 2.

NO : The diagnosis is complete.

STEP 2. Check whether the diagnostic trouble code is reset.

Replace the keyless operation key for which the DTC is set with a new one, register the key ID and keyless operation key ID and check whether the DTC is reset.

1. Erase the DTC.
2. Turn the ignition switch from the LOCK (OFF) position to the ON position.
3. Check if the DTC is set.

Q: Is the DTC set?

YES : Replace KOS-ECU and register the ID codes.

NO : The diagnosis is complete.