Code
No. B1476 ON power supply open circuit (Fuse No. 15 circuit) Code No. B1477 ON power
supply open circuit (Fuse No. 21 circuit)
OPERATION
The auxiliary battery power supply is supplied from the electric motor switch to SRS-ECU. SRS-ECU has two independent battery power supplies circuit (fuse Nos. 15 and 21) having
fuses.
TROUBLE JUDGEMENT
The code is set when the voltage between the SRS-ECU terminal No. 37 or No. 43 and the
earth drops below the specified value for 5 seconds continuously. Also, if the code No. B1476
and B1477 are set at the same time, the battery voltage may have dropped. Therefore, check the
battery first.
PROBABLE CAUSES
Damaged wiring harness and connectors
Malfunction of SRS-ECU
DIAGNOSIS PROCEDURE
STEP 1. Check junction block fuse number 15 or 21.
Q.
Is the fuse burned out?
Go to Step 2
Go to Step 4
STEP 2.Voltage measurement at the B-112 SRS-ECU connector
(1)Check that the negative auxiliary battery terminal is disconnected.
If the negative auxiliary battery terminal is connected, disconnect it.
(2)Disconnect 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.
Take the measurements below at the B-112 harness side connector.
Voltage between terminal No. 37/43 and body
earth
OK: 9 V or more
(6)Disconnect the negative auxiliary battery terminal.
Q.
Is the check result normal?
Go to Step 7
Go to Step 3
STEP 3. Check the wiring harness between B-112 SRS-ECU connector terminal
No. 37/43 and the electric motor switch.
note
Before checking the wiring harness, check junction block connectors B-303,
B-302 and joint connectors B-05, B-06, and repair them if necessary.
Open circuit check for the SRS-ECU power supply wire
Q.
Is the check result normal?
Go to Step 7
Repair the harness
STEP 4. Fuse open circuit check
(1)Replace the fuse.
(2)Turn the electric motor switch to the "ON" position, wait for at
least one minute and then turn the switch off.
(3)Check the fuse.
Q.
Is the fuse in good condition?
This diagnosis is complete.
Go to Step 5
STEP 5. Resistance measurement at the B-303 junction block connector
(check for the SRS-ECU power supply wire)
(1)Disconnect B-303 junction block connector.
(2)Disconnect B-112 SRS-ECU connector.
(3)
caution
Do not insert a test probe into the
terminal from its front side directly as the connector contact pressure may be weakened.
Take the following measurements at B-303 junction block connector (harness
side).
Continuity between terminal No. 5/8
and body earth
OK: No continuity
Q.
Is the check result normal?
Go to Step 6.
Repair the wiring harness between B-303 junction block connector
terminal No. 5 or 8 and B-112 SRS-ECU connector terminal No. 37 or 43.
STEP 6. Resistance measurement at the B-305 junction block connector
(check for the SRS warning lamp power supply wire)
(1)Disconnect B-305 junction block connector.
(2)Disconnect B-101 combination meter connector.
(3)
caution
Do not insert a test probe into the
terminal from its front side directly as the connector contact pressure may be weakened.
Take the measurements below at B-305 harness side connector.
Continuity between terminal No. 6 and
body earth
OK: No continuity
Q.
Is the check result normal?
Check the other circuit, which flows through fuse number 15 (Refer
to GROUP 90, Circuit Diagrams). Then go to Step 7.
Repair the wiring harness between B-305 junction block connector
terminal No. 6 and B-101 combination meter (SRS warning lamp) connector No 2.
STEP 7. Check whether the diagnosis code is reset.
Q.
Is diagnosis code B1476 or B1477 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with
Intermittent Malfunction ).
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Go to Step 2
Go to Step 4
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