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












OPERATION



TROUBLE JUDGEMENT



PROBABLE CAUSES



  • Damaged wiring harness and connector
  • Seat belt pre-tensioner (driver’s side) (squib) harness shorted to earth.
  • Malfunction of SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. 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)Disconnect seat belt pre-tensioner (driver’s side) connector C-18 <LHD> or C-31 <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 C-18 <LHD> or C-31 <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 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 B-111 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-111 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.
Disconnect seat belt pre-tensioner (driver’s side) connector C-18 <LHD> or C-31 <RHD>. Use a flat-tipped screwdriver to pull out the locking button at the harness side connector, and then 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 51/52 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-111 harness side connector.

  • Continuity between terminal No. 51/52 and body earth
OK: No continuity

Q. Is the check result normal?

Go to Step 3

Repair the wiring harness between the B-111 SRS-ECU connector terminal No. 51/52 and the C-18 <LHD> or C-31 <RHD> seat belt pre-tensioner connector (driver’s side) (terminal No.2 and 1).

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 ).