42A-B1A08 Keyless/F.A.S.T. key 1 fail

DTC B1A08 Keyless/F.A.S.T. key 1 fail
DTC B1A09 Keyless/F.A.S.T. key 2 fail
DTC B1A0A Keyless/F.A.S.T. key 3 fail
DTC B1A0B Keyless/F.A.S.T. key 4 fail
DTC B1A0C Keyless key 5 fail
DTC B1A0D Keyless key 6 fail
DTC B1A0E Keyless key 7 fail
DTC B1A0F Keyless key 8 fail

When replacing the ECU, always check that the communication circuit is normal.
When this diagnostic trouble code is set as "historic fault", clear it. Then, when the diagnostic trouble code is not set as "current fault" by operating the keyless entry system again, no action must be taken.

DIAGNOSTIC FUNCTION

The door locking/unlocking code is automatically updated every time the doors are locked (rolling code). ETACS-ECU sets DTC No. B1A08, B1A09, B1A0A, B1A0B, B1A0C, B1A0D, B1A0E, or B1A0F when it receives wrong signal (rolling code out of synchronization) from the transmitter.

note	When the system is corrected by the keyless entry operation, the diagnostic trouble code will be set as "historic fault."

TECHNICAL DESCRIPTION (COMMENT)

B1A08: ETACS-ECU determines that the abnormality is present when the rolling code received from the transmitter 1 (the first transmitter registered in ETACS-ECU) greatly differs from the rolling code stored in ETACS-ECU.
B1A09: ETACS-ECU determines that the abnormality is present when the rolling code received from the transmitter 2 (the second transmitter registered in ETACS-ECU) greatly differs from the rolling code stored in ETACS-ECU.
B1A0A: ETACS-ECU determines that the abnormality is present when the rolling code received from the transmitter 3 (the third transmitter registered in ETACS-ECU) greatly differs from the rolling code stored in ETACS-ECU.
B1A0B: ETACS-ECU determines that the abnormality is present when the rolling code received from the transmitter 4 (the fourth transmitter registered in ETACS-ECU) greatly differs from the rolling code stored in ETACS-ECU.
B1A0C: ETACS-ECU determines that the abnormality is present when the rolling code received from the transmitter 5 (the fifth transmitter registered in ETACS-ECU) greatly differs from the rolling code stored in ETACS-ECU.
B1A0D: ETACS-ECU determines that the abnormality is present when the rolling code received from the transmitter 6 (the sixth transmitter registered in ETACS-ECU) greatly differs from the rolling code stored in ETACS-ECU.
B1A0E: ETACS-ECU determines that the abnormality is present when the rolling code received from the transmitter 7 (the seventh transmitter registered in ETACS-ECU) greatly differs from the rolling code stored in ETACS-ECU.
B1A0F: ETACS-ECU determines that the abnormality is present when the rolling code received from the transmitter 8 (the eighth transmitter registered in ETACS-ECU) greatly differs from the rolling code stored in ETACS-ECU.

note

When you press the unlock switch after you press the lock/unlock switches on the transmitter 100 times or more at the place where an authorized vehicle is not within a radio wave range, the system will not be unlocked only once. Then the diagnostic trouble code is set as "current fault." When you press the unlock switch again, the system will be unlocked. Then the "current fault" is switched to "historic fault." When you press the lock switch after you press the lock/unlock switches 100 times or more, the system will be locked. Then the diagnostic trouble code is set as "current fault." When you press the lock switch again, the system will be locked. Then the "current fault" is switched to "historic fault."
When you press the unlock or lock switch after you press the lock/unlock switches on the transmitter 3000 times or more at the place where an authorized vehicle is not within a radio wave range, the system will not be blocked. Then the diagnostic trouble code is set as "current fault." Then, when the keyless ID is registered again, the diagnostic trouble code is set as "historic fault" instead of "current fault".

TROUBLESHOOTING HINTS

Rolling code out of synchronization
Malfunction of the transmitter
Malfunction of the ETACS-ECU

DIAGNOSIS

STEP 1. Synchronize the rolling code and recheck the DTC.

(1) Synchronize the rolling code.

Push the lock switch or unlock switch of transmitter twice or more.
If the keyless entry system does not resume by the procedure above, register the key again (Refer to ).

(2) Recheck if the DTC is set.

(1) Push the lock switch or unlock switch of transmitter.

(2) Check if the DTC is set.

Is the DTC set?

Go to Step 2

The diagnosis is complete.

STEP 2. Check whether the DTC is set again.

Replace the transmitter by which the DTC is set with a new one, register the key (Refer to

.), and recheck if the DTC is set.

(1) Push the lock switch or unlock switch of transmitter.

(2) Erase the DTC.

(3) Check if the DTC is set.

Is the DTC set?

Replace ETACS-ECU and register the ID codes (Refer to

The diagnosis is complete.