DTC B1207: Passenger’s Air Bag OFF Indicator Light (Short Circuit between Circuit Terminal)

caution

If DTC B1207 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 the passenger’s air bag OFF indicator light driving circuit is short to ground.

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

."
(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. Resistance measurement at the C-122 SRS-ECU connector.

(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 C-122 harness side connector terminal No.18 and body ground.
It should be open circuit.

Q. Is it open circuit?

Go to Step 5.

Repair the wiring harnesses between the C-122 SRS-ECU connector terminal No. 18 and the C-18 instrument center panel connector No.11. Then go to Step 6

STEP 5. Resistance measurement at the C-122 SRS-ECU connector.

(1)Disconnect the negative battery terminal.

(3)

caution

Do not insert a probe into the terminal from its front side directly, as the connector contact pressure may be weakened.

Check for continuity between the C-122 harness side connector terminal No.18 and body ground.
It should be open circuit.

Q. Is it open circuit?

Go to Step 6.

Replace SRS-ECU (Refer to

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 B1207 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 ).