[Previous][Next]
DTC B1476 IG1 power supply open circuit (fuse No.16 circuit)
 
 
cautionIf DTC B1476 is set in SRS-ECU, be sure to diagnose the CAN bus line.
 
 
OPERATION
The battery power supply is supplied from the fusible link (40) <Up to 20 Model year> or (36) <From 22 Model year> to SRS-ECU.
SRS-ECU has two independent battery power supplies circuit (fuse No.16) having fuses.
 
 
TROUBLE JUDGMENT
The code is set when the voltage between the IG1 terminal (SRS-ECU IG1A line) and the ground drops below the specified value for 5 seconds continuously. Also, if DTC B1476 is set at the same time, the battery voltage may have dropped. Therefore, check the battery first.
 
 
PROBABLE CAUSES
  • 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 the ignition switch to the "ON" position, wait for at least one minute, and then turn the switch "LOCK" (OFF).
(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 the ignition switch to the "LOCK" (OFF) position 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 the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the CAN bus line found to be normal?
Go to Step 4.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ). Then go to Step 4.
 
STEP 4. Using scan tool (M.U.T.-IIISE), check whether the other system DTC is set.
Check the ETACS DTC.
Is the DTC set?
Diagnose the ETACS (Refer to GROUP 54A - ETACS - Troubleshooting ).
Check the input signal of ETACS-ECU ignition switch (IG1) (Refer to GROUP 54A - Symptom Procedures ). Then go to Step 5.
 
STEP 5. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
(1) Connect the negative battery terminal.
(2) After erasing the DTC memory, check the DTC again.
(3) Disconnect the negative battery terminal.
Is DTC B1476 set?
Go to Step 6.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
 
STEP 6. Resistance measurement at the SRS-ECU connector.
(1) Disconnect the SRS-ECU connectors.
(2) Take the measurements below at the SRS-ECU wiring harness side connectors.
  • Continuity GND2 line between SRS-ECU wiring harness side connector and body ground
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 7.
Repair the wiring harness GND2 line between the SRS-ECU connector and the ground.
 
STEP 7. Voltage 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 SRS-ECU connector.
(3) Connect the negative battery terminal.
(4) Ignition switch: ON
(5) Take the measurements below at the SRS-ECU harness side connector.
  • Voltage between terminal IG1A line and body ground
OK: 9 volts 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 ETACS-ECU connector.
(3) Disconnect the SRS-ECU connector.
(4)
  • Continuity IG1A line between ETACS-ECU connector and SRS-ECU connector
OK: The resistance should be 2 ohms or less
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. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Is DTC B1476 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 ).