Code No.B1609 Seat belt pre-tensioner (passenger’s side) (squib) system (short-circuit between terminals of the squib circuit)












OPERATION



TROUBLE JUDGEMENT



PROBABLE CAUSES



  • Damaged short spring *
  • Short circuit between terminals of seat belt pre-tensioner (passenger’s side) (squib) circuit
  • Damaged connector(s)
  • Malfunction of SRS-ECU
note *: The squib circuit connectors integrate a short spring (which prevents the seat belt pre-tensioner from being unintentionally deployed because of static electricity by shorting the positive wire to the earth wire in the squib circuit when the connectors are disconnected). Therefore, when the above codes are set, the short spring may not be released due to the damaged connector even when the connectors are connected.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code.

Q. Is diagnosis code B1519 set?
Go to Step 2
Go to Step 3

STEP 2. Connector lock check: B-113 SRS-ECU connector.
(1)Check that the negative auxiliary battery terminal is disconnected. If the negative auxiliary battery terminal is connected, disconnect it.
(2)Disconnect the connector B-113 and then reconnect it.
(3)Connect the negative auxiliary battery terminal.
(4)After erasing the diagnosis code memory, check the diagnosis code again.
(5)Disconnect the negative auxiliary battery terminal.

Q. Is diagnosis code B1609 set?
Go to Step 3
The procedure is complete. It is assumed that diagnosis code B1609 set as connector B-113 was engaged improperly.

STEP 3. Connector lock check: B-113 SRS-ECU connector and C-31 <LHD> and C-18 <RHD> seat belt pre-tensioner connector (passenger’s side).
(1)Check that the negative auxiliary battery terminal is disconnected. If the negative auxiliary battery terminal is connected, disconnect it.

(2)After disconnecting B-113 SRS-ECU and front passenger’s pre-tensioner connector (harness side), reconnect the connector. For the connector disconnection, use the use the flat-tipped screwdriver to pull out the harness side connector locking button. After releasing the lock, disconnect the connector.
(3)Connect the negative auxiliary battery terminal.
(4)After erasing the diagnosis code memory, check the diagnosis code again.
(5)Disconnect the negative auxiliary battery terminal.

Q. Is diagnosis code B1609 set?

Go to Step 4

The procedure is complete. It is assumed that diagnosis code B1609 set as connector B-113 or C-31 <LHD> and C-18 <RHD> was engaged improperly.

STEP 4. Diagnosis check by dummy resistor connection.
(1)Check that the negative auxiliary battery terminal is disconnected. If the negative auxiliary battery terminal is connected, disconnect it.

(2)After disconnecting B-113 SRS-ECU and front passenger’s pre-tensioner connector (harness side), reconnect the connector. For C-31 <LHD> and C-18 <RHD> connector disconnection, use the flat-tipped screwdriver to pull out the harness side connector locking button. After releasing the lock, disconnect the connector.

(3)Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991884).
(4)Connect special tool resistor harness to the C-31 <LHD> and C-18 <RHD> harness side connector.
(5)Connect the negative auxiliary battery terminal.
(6)After erasing the diagnosis code memory, check the diagnosis code again.
(7)Disconnect the negative auxiliary battery terminal.

Q. Is the diagnosis code No. B1609 set?

Go to Step 5

Replace the seat belt with pre-tensioner (passenger’s side) (Refer to ).

STEP 5. Resistance measurement at the B-113 SRS-ECU connector.
(1)Check that the negative auxiliary battery terminal is disconnected. If the negative auxiliary battery terminal is connected, disconnect it.
(2)Disconnect the B-113 SRS-ECU connector.

(3)
danger To release the SRS-ECU connector short spring in the following operations, disconnect this seat belt pre-tensioner connector, and keep the squib circuit shorted.
Use the flat-tipped screwdriver to pull out the locking button at the front passenger’s pre-tensioner connector (wiring harness side), then unlock and disconnect the connector.

(4)
caution The short spring may not be released due to the insufficient insertion. Therefore, insert the insulator for 4 mm or more.
Insert an insulator (width: 3 mm, thickness: 0.5 mm) such as cable tie between the terminal 5/6, and the short spring, and 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.
Take the measurements below at the B-113 harness side connector.

  • Continuity between terminals 5 and 6
OK: No continuity

Q. Is the check result normal?

Go to Step 6.

Repair the wiring harness between the B-113 SRS-ECU connector terminal No. 5/6 and the C-31 <LHD> and C-18 <RHD> seat belt pre-tensioner connector terminal No. 2/1.

STEP 6. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1609 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).