Code No.B1612: Seat belt pre-tensioner (passenger’s side) (squib) system (short-circuited to the power supply)






OPERATION




DIAGNOSIS CODE SET CONDITIONS




PROBABLE CAUSES



  • Damaged wiring harnesses or connectors
  • Short to the power supply in the seat belt pre-tensioner (passenger’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 (passenger’s side) connector D-23 <LHD> or D-15 <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-23 <LHD> or D-15 <RHD> harness side connector.
(5)Connect the negative battery terminal.
(6)Erase diagnosis code memory, and then check the diagnosis code.

Q. Is diagnosis code B1612 set?

Go to Step 2.

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

STEP 2. Voltage 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 deploying unintentionally, disconnect the seat belt pre-tensioner (passenger’s side) connector D-23 <LHD> or D-15 <RHD> to short the squib circuit.
Disconnect seat belt pre-tensioner (passenger’s side) connector D-23 <LHD> or D-15 <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 4 mm or more, otherwise the short spring will not be released.
Insert a cable tie [3 mm wide, 0.5 mm thick] between terminals 27, 28 and the short spring to release the short spring.
(5)Connect the negative battery terminal.
(6)Turn the ignition switch to the "ON" position,

(7)
caution Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.
Voltage measurement between C-130 harness side connector terminals 27, 28 and body earth.
OK: 1 V or less

Q. Is the check result normal?

Go to Step 3.

Repair the harness wires between SRS-ECU connector C-130 (terminal No.27 and 28) and the seat belt pre-tensioner (passenger’s side) connector D-23 <LHD> or D-15 <RHD> (terminal No.2 and 1)

STEP 3. Check whether the diagnosis code is reset.


Q. Is diagnosis code B1612 set?

Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).