Code No.B1605: Seat belt pre-tensioner (driver’s side) (squib) system (short-circuited to the earth)




OPERATION



DIAGNOSIS CODE SET CONDITIONS



PROBABLE CAUSES



  • Damaged wiring harnesses or connectors
  • Short to the earth in the seat belt pre-tensioner (driver’s side) (squib) harness
  • Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the diagnosis code by connecting a dummy resistor. (M.U.T.-III diagnosis code)
(1)Disconnect the negative battery terminal.


(2)Disconnect seat belt pre-tensioner (driver’s side) connector D-15 <LHD> or D-23 <RHD>. Use a flat-tipped screwdriver to pull out the locking button at the harness side connector, and then disconnect the connector.

(3)Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991884).
(4)Connect special tool (MB991884) to the D-15 <LHD> or D-23 <RHD> harness side connector.
(5)Connect the negative battery terminal.
(6)Erase diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code B1605 set?

Go to Step 2.

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

STEP 2. Resistance measurement at the SRS-ECU connector C-130.
(1)Disconnect the negative battery terminal.

(2)Disconnect SRS-ECU connector C-130.


(3)
danger To prevents the seat belt pre-tensioner from operating unintentionally, disconnect the seat belt pre-tensioner (driver’s side) connector D-15 <LHD> or D-23 <RHD> to short the squib circuit.
Disconnect seat belt pre-tensioner (driver’s side) connector D-15 <LHD> or D-23 <RHD>. Use a flat-tipped screwdriver to pull out the locking button at the harness side connector, and then 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 29, 30 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.
Resistance measurement between C-130 harness side connector terminals 29, 30 and body earth.
OK: Open circuit

Q. Is the check result normal?

Go to Step 3.

Repair the harness wire between SRS-ECU connector C-130 (terminal No.29 and 30) and the seat belt pre-tensioner (driver’s side) connector D-15 <LHD> or D-23 <RHD> (terminal No.1 and 2)

STEP 3. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1605 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).