Code No.B1551:
SRS warning lamp circuit malfunction (Lamp does not switch off)
OPERATION
The auxiliary battery power supply is supplied from the electric motor switch to the SRS
warning lamp. When SRS-ECU operates normally, the SRS warning lamp is illuminated for 6 to 8 seconds
after the electric motor switch is turned to the "ON" position, and extinguished afterward.
TROUBLE JUDGEMENT
This diagnosis code will be set if an open circuit has occurred in the wiring harness
between the combination meter and the SRS-ECU.
PROBABLE CAUSES
Damaged wiring harnesses of connectors
Malfunction of the SRS-ECU
Malfunction of the combination meter
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III diagnosis code.
Q.
Is diagnosis code set?
Carry out the diagnosis for the set code. (Refer to )
Then go to Step 4.
Go to Step 2
STEP 2. Check the harness between the B-112 SRS-ECU connector (terminal
No.39) and the B-101 combination meter connector (terminal No.15).
Check the SRS warning lamp output lines for open circuit.
Q.
Is the check result normal?
Go to Step 3
Repair the harness wires. Then go to Step 4.
STEP 3. Check the SRS warning lamp.
(1)Check that the negative auxiliary battery terminal is disconnected. If the negative
auxiliary battery terminal is connected, disconnect it.
(2)Disconnected the B-112 SRS-ECU connector.
(3)Connect the negative auxiliary battery terminal.
(4)Electric motor switch to the "ON" position.
(5)
caution
Do not insert a test probe into the
terminal from its front side directly, as the connector contact pressure may be weakened.
Check that SRS warning lamp turn "ON" when SRS-ECU connector B-112 is disconnected. Check
that the same warning lamp turn "OFF" when the terminal No.39 of the above connector is earthed.
Q.
Is the check result normal?
Go to Step 4
Replace the combination meter (Refer to GROUP 54A, Combination Meter ).
STEP 4. Check whether the diagnosis code is reset.
Q.
Is diagnosis code B1551 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with
Intermittent Malfunction ).
)
)
)
)
)
Carry out the diagnosis for the set code. (Refer to 
)
Then go to Step 4.
Go to Step 2