Code No.B1410: Passenger’s (Front) Air Bag Module (1st Squib) System Fault 1 (Short Circuit between Terminals of the Squib Circuit)
Code No.B1490: Passenger’s (Front) Air Bag Module (2nd Squib) System Fault 1 (Short Circuit between Terminals of the Squib Circuit)




caution If diagnosis code B1410 <1st squib> or B1490 <2nd squib> is set in the SRS-ECU, always diagnose the CAN main bus line.

OPERATION



DIAGNOSIS CODE SET CONDITIONS


This diagnosis code is set if there is abnormal resistance between the input terminals of the passenger’s side air bag module (squib).

PROBABLE CAUSES



note *: The squib circuit connectors integrate a "short" spring (which prevents the air bag from deploying unintentionally due to static electricity by shorting the positive wire to the earth wire in the squib circuit when the connectors are disconnected). (Refer to ). Therefore, if connector C-119 or C-108 is damaged or improperly engaged, the short spring may not be released when the connector is connected.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2 .
Repair the CAN bus line (Refer to GROUP 54F, Diagnosis ).

STEP 2. Check whether the diagnosis code is reset.
Check again if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Ignition: LOCK (OFF) position to ON
(3)On completion, check that the diagnosis code is not reset.

Q. Is the diagnosis code 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. M.U.T.-III diagnosis code
caution To prevent damage to M.U.T.-III, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting M.U.T.-III.
(1)Turn the ignition switch to the "ON" position.
(2)Check if the diagnosis code is set.
(3)Turn the ignition switch to the "LOOK" (OFF) position.

Q. Is diagnosis code B1519 set?
Go to Step 4 .
Go to Step 5 .

STEP 4. Connector check: SRS-ECU connector C-119.;

Q. Is the connector correctly engaged?

Go to Step 5 .

Engage the connector correctly. Then go to Step 9 .

STEP 5. Connector check: SRS-ECU connector C-119 and passenger’s air bag module connector C-108 (M.U.T.-III diagnosis code).
(1)Disconnect the negative battery terminal.


(2)Disconnect connectors C-119 and C-108, and then reconnect them.

(3)Slide the outer housing of the clock spring side of passenger’s air bag module connector C-108 in the arrow direction shown, and disconnect the connector.
(4)Connect the negative battery terminal.
(5)Erase the diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code B1410 <1st squib> or B1490 <2nd squib> set?

Go to Step 6 .

The procedure is complete. It is assumed that diagnosis code B1410 <1st squib> or B1490 <2nd squib> set as connector C-119 or C-108 was engaged improperly.

STEP 6. Check the passenger’s air bag module (M.U.T.-III diagnosis code).
(1)Disconnect the negative battery terminal.

(2)Disconnect the passenger’s air bag module connector C-108.

(3)Slide the outer housing of the clock spring side of passenger’s air bag module connector C-108 in the arrow direction shown, and disconnect the connector.

(4)Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991866).
(5)
caution Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
Insert special tool MB991866 into the harness side connector C-108 (terminal No.1 and 2 <1st squib> or terminal No.3 and 4 <2nd squib>) by backprobing.
(6)Connect the negative battery terminal.
(7)
caution Always diagnosis code B1491 is set when checking diagnosis code B1410. This is because the second side terminal is isolated when checking it, diagnosis code B1491 is set but this is not a fault. In addition, always diagnosis code B1411 is set when checking diagnosis code B1490 because the first side terminal is isolated.
Erase the diagnosis code memory, and check the diagnosis code.

Q. Is the checked diagnosis code set?

Go to Step 7 .

Replace the passenger’s air bag module (Refer to ). Then go to Step 9 .

STEP 7. Check the passenger’s air bag module circuit at SRS-ECU connector C-119.

(1)Disconnect SRS-ECU connector C-119.

(2)
danger To prevent the air bag from deploying unintentionally, disconnect the passenger’s air bag module connector C-108 to short the squib circuit.
Disconnect the passenger’s air bag module connector C-108.

(3)Slide the outer housing of the clock spring side of passenger’s air bag module connector C-108 in the arrow direction shown, and disconnect the connector.


(4)
caution Insert an insulator such as a cable tie to a depth of 4mm or more, otherwise the short spring will not be released.
Insert a cable tie [3 mm wide, 0.5 mm thick] between terminals 27 and 28 <1st squib> or 30 and 31 <2nd squib>, and the short spring to release the short spring.


(5)
caution Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
Check for continuity between C-119 harness side connector terminals 27 and 28 <1st squib> or 30 and 31 <2nd squib>.
OK: Open circuit

Q. Is the check result normal?

Erase the diagnosis code memory, and check the diagnosis code. If diagnosis code B1410 <1st squib> or B1490 <2nd squib> set, replace the SRS-ECU (Refer to ). Then go to Step 9 .

Go to Step 8 .

STEP 8. Check the harness for short circuit between SRS-ECU connector C-119 (terminal No.27 and 28 <1st squib> or terminal No.30 and 31 <2nd squib>) and passenger’s air bag module connector C-108 (terminal No.1 and 2 <1st squib> terminal No.4 and 3 <2nd squib>).


Q. Are harness wires between SRS-ECU connector C-119 (terminal No.27 and 28 <1st squib> or terminal No.30 and 31 <2nd squib>) and passenger’s air bag module connector C-108 (terminal No.1 and 2 <1st squib> terminal No.4 and 3 <2nd squib>) in good condition?

Go to Step 9 .

Replace the harness wires between SRS-ECU connector C-119 and passenger’s air bag module connector C-108. Then go to Step 9 .

STEP 9. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1410 <1st squib> or B1490 <2nd squib> set?
Return to Step 1.
The procedure is complete.