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DTC B1476: IG1 power supply open circuit (Fuse No. 16 circuit)
 
 
cautionIf DTC B1476 (fuse No. 16) is set in the SRS-ECU, be sure to diagnose the CAN bus line.
 
 
CIRCUIT OPERATION
SRS-ECU has two independent battery power supplies circuit (fuse Nos. 16) having fuses.
 
 
DTC SET CONDITIONS
The code is set when the voltage between the IG1 terminal (SRS-ECU terminal IG1A) and the ground drops below the specified value for 5 seconds continuously. Also, if code No. B1476 are set at the same time, the battery voltage may have dropped. Therefore, check the battery first.
 
 
TROUBLESHOOTING HINTS
  • Open circuit to power supply circuit
  • Damaged wiring harness and connectors
  • Malfunction of SRS-ECU
  • Malfunction of ETACS-ECU
 
 
DIAGNOSIS
STEP 1. Power supply fuse check.
Is the fuse in good condition?
Go to Step 3.
Go to Step 2.
 
STEP 2. Fuse open circuit check
(1) Replace the fuse.
(2) Turn on the power supply mode of the electric motor switch, wait for at least one minute, and then turn off the power supply mode of the electric motor switch.
(3) Check the fuse.
Is the fuse in good condition?
Go to Step 3.
Repair the wiring harness IG1A line between the ETACS-ECU connector and the SRS-ECU connector, and replace the power supply fuse.
 
STEP 3. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the scan tool ."
(2) Turn on the power supply mode of the electric motor switch.
(3) Diagnose the CAN bus line.
(4) Turn off the power supply mode of the electric motor switch.
Is the CAN bus line found to be normal?
Go to Step 4.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
 
STEP 4. Using scan tool (M.U.T.-IIISE), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to How to connect the Scan Tool .
(2) Turn off the power supply mode of the electric motor switch.
(3) Check the ETACS data list.
  • Turn on the power supply mode of the electric motor switch.
 
Item No.Item nameNormal condition
254IG voltageBattery positive voltage
OK: Normal condition is displayed.
Is the check result normal?
Go to Step 5.
Refer to GROUP 54A, Inspection Procedure 2 "The OSS-ECU (IG1) signal is not received ."
 
STEP 5. Recheck for DTC.
Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn on the power supply mode of the electric motor switch.
(3) Check if the DTC is set.
(4) Turn off the power supply mode of the electric motor switch.
Is the DTC set?
Go to Step 6.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 6. Resistance measurement at the SRS-ECU connector.
(1) While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the SRS-ECU connectors.
(2) Take the measurements below at the wiring harness side connectors.
  • Continuity GND2 line between wiring harness side connector and body ground
OK: Continuity (less than 2 Ω)
Is the check result normal?
Go to Step 7.
Repair the wiring harness GND2 line between the SRS-ECU connector and the body ground.
 
STEP 7. Voltage measurement at the SRS-ECU connector (IG1A line).
(1) Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
(2) While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the SRS-ECU connector.
(3) Connect the negative battery terminal.
(4) Electric motor switch: ON
(5) Take the measurements below at the harness side connector.
  • Voltage IG1A line between SRS-ECU connector and body ground
OK: 9 V or more
(6) Disconnect the negative battery terminal.
Is the check result normal?
Go to Step 9.
Go to Step 8.
 
STEP 8. Resistance measurement at the SRS-ECU connector.
(1) Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
(2) Disconnect the junction block connector.
(3) While pushing the part "A" indicated in the figure of the harness side connector, turn the lock lever to the direction of the arrow to release the lock lever, and disconnect the SRS-ECU connector.
(4)
  • Continuity IG1A line between ETACS-ECU connector and SRS-ECU connector
OK: Continuity (less than 2 Ω)
Is the check result normal?
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ).
Repair the wiring harness IG1A line between the ETACS-ECU connector and the SRS-ECU connector.
 
STEP 9. Recheck for DTC.
Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn on the power supply mode of the electric motor switch.
(3) Check if the DTC is set.
(4) Turn off the power supply mode of the electric motor switch.
Is DTC B1476 or B1477 set?
Replace SRS-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).