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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





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




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 ."
(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?

Go to Step 2.

Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).

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?

Go to Step 3.
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 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 ).

Q. Is the check result normal?

Go to Step 4.
Replace instrument center panel (Refer to GROUP 52A - Instrument Panel Assembly ).

STEP 4. Check the harness for open circuit between SRS-ECU connector C-122 (terminal No.18) and the instrument center panel connector C-18 (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-122 SRS-ECU connector.
(3)Disconnect the instrument center panel connector C-18.

(4)Check for continuity between the following terminals. It should be less than 2 ohms.

  • SRS-ECU connector C-122 (terminal No.18) and the instrument center panel connector C-18 (terminal No.11)

Q. Does continuity exist?

Go to Step 5.

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-18 instrument center panel connector.
(3)Connect the negative battery terminal.
(4)Ignition switch: ON.

(5)Measure the voltage between the C-18 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)?

Go to Step 6.

Repair the wiring harness between the C-317 ETACS-ECU connector terminal No. 5 and the C-18 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?

Replace SRS-ECU (Refer to ).
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).