Code No.72: Side-airbag module (squib) (RH) system (open-circuited in the squib circuit)

OPERATION

The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors. If the impact is over a predetermined level, the SRS-ECU outputs an ignition signal. At this time, if the side-airbag safing G-sensor is on, the SRS side-airbag will inflate.
The ignition signal is input to the side-airbag module to inflate the side-airbag.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if the side-airbag squib (RH) wire(s) are open-circuited. However, if no diagnosis code resets, the SRS warning lamp will be switched off (diagnosis code will be retained).

PROBABLE CAUSES

Open circuit in the side-airbag module (RH) (squib) circuit
Improper connector contact
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 the side-airbag module (RH) connector D-29.

(3)Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991866).
(4)

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 D-29 harness side connector by backprobing.
(5)Connect the negative battery terminal.
(6)Erase the diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code 72 set?

Go to Step 2.

Replace the frame assembly (Refer to GROUP 52A, Front Seat

STEP 2. Resistance measurement between SRS-ECU connector C-146 (terminal No.23 and 24) and the side-airbag module (RH) connector D-29 (terminal No.1 and 2).

(1)Disconnect SRS-ECU connector C-146 and side-airbag module (RH) connector D-29.

(2)

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 the following terminals.

SRS-ECU connector C-146 terminal No.23 and the side-airbag module (RH) connector D-29 terminal No.2
SRS-ECU connector C-146 terminal No.24 and the side-airbag module (RH) connector D-29 terminal No.1

OK: Less than 2 Ω

Q. Are the check results normal?

Go to Step 3.

Repair the harness wires between SRS-ECU connector C-146 (terminal No.23 and 24) and side-airbag module (RH) connector D-29 (terminal No.1 and 2).

STEP 3. Check whether the diagnosis code is reset.

Q. Is diagnosis code 72 set?

	Replace the SRS-ECU (Refer to ).

	An intermittent malfunction is suspected (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points ).