B1206
DTC B1206: Passenger's Air Bag OFF Indicator Light (Open Circuit)
CAUTION:
If DTC B1206 is set in the SRS-ECU, always diagnose the CAN main bus line.
CIRCUIT OPERATION
- Power for the passenger's air bag OFF indicator light is supplied from the fusible link (34).
- The passenger's air bag OFF indicator light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system. In the following situations, the indicator will stay on to show that the passenger's (front) air bag is not operational.
- The occupant is determined to be less than 66 lbs (30 kg) by the occupant classification-ECU.
- The front passenger's seat is not occupied.
DTC SET CONDITIONS
This DTC will be set if an open circuit has occurred in the wiring harness between the passenger's air bag OFF indicator light and the SRS-ECU.
TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Malfunction of the SRS-ECU
- Malfunction of the passenger's air bag OFF indicator light
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN Communication System)
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK"
(OFF) position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958. Refer to "How to connect the scan tool Reading and Clearing Diagnostic Trouble Codes."
(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.
Q. Is the CAN bus line found to be normal?
YES Go to Step 2.
NO Repair the CAN bus line CAN Bus Diagnostics Chart).
STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1)Erase the DTC.
(2)Turn the ignition switch to the "ON" position.
(3)Check if the DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
Q. Is the DTC set?
YES Go to Step 3.
NO There is an intermittent malfunction such as poor engaged connector(s) or open circuit How to Cope With Intermittent Malfunctions).
STEP 3. Check the passenger's air bag OFF indicator light.
(1)It is checked whether the passenger's air bag OFF indicator light is normal
(Refer to Passenger's Air Bag Off Indicator Light Check).
Q. Is the check result normal?
YES Go to Step 4.
NO Replace instrument center panel Instrument Panel Assembly Removal and Installation).
STEP 4. Check the harness for open circuit between SRS-ECU connector C-37 (terminal No.18) and the instrument center panel connector C-124 (terminal No.11).
(1)Disconnect the negative battery terminal.
(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 C-37 SRS-ECU connector.
(3)Disconnect the instrument center panel connector C-124.
(4)Check for continuity between the following terminals. It should be less than 2 ohms.
- SRS-ECU connector C-37 (terminal No.18) and the instrument center panel connector C-124 (terminal No.11)
Q. Does continuity exist?
YES Go to Step 5.
NO Repair the harness wires.
STEP 5. Measure the voltage at the instrument center panel connector.
(1)Disconnect the negative battery terminal.
(2)Disconnect the C-124 instrument center panel connector.
(3)Connect the negative battery terminal.
(4)Ignition switch: ON.
(5)Measure the voltage between the C-124 harness side connector terminal No. 8 and body ground.
- The voltage should measure approximately 12 volts (battery positive voltage).
Q. Is the measured voltage approximately 12 volts (battery positive voltage)?
YES Go to Step 6.
NO Repair the wiring harness between the fusible link (34) and the C-124 instrument center panel connector terminal No. 8.
STEP 6. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1)Erase the DTC.
(2)Turn the ignition switch to the "ON" position.
(3)Check if the DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
Q. Is DTC B1206 set?
YES Replace SRS-ECU (Refer to Service and Repair).
NO There is an intermittent malfunction such as poor engaged connector(s) or open circuit How to Cope With Intermittent Malfunctions).