Code No.81: Side-airbag module (squib) (LH) system (short-circuited between terminals of 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 one side-airbag squib (LH) wire shorted to the other. However, if no diagnosis code resets, the SRS warning lamp will be switched off (diagnosis code will be retained).

PROBABLE CAUSES

Improper engaged connector or defective short spring*
Short circuit between the side-airbag module (LH) (squib) circuit terminals
Damaged connector(s)
Malfunction of the SRS-ECU

note

*: The squib circuit connectors integrate a "short" spring (which prevents the air bag from deploying unintentionally due to static electricity by shorting the positive wire to the earth wire in the squib circuit when the connectors are disconnected). (Refer to

). Therefore, if connector C-146 or D-18 is damaged or improperly engaged, the short spring may not be released when the connector is connected.

DIAGNOSIS PROCEDURE

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

Q. Is diagnosis code 34 set?

	Go to Step 2.

	Go to Step 3.

STEP 2. Connector lock check: SRS-ECU connector C-146 (M.U.T.-III diagnosis code).

(1)Disconnect the negative battery terminal.

(2)Disconnect connectors C-146 and then reconnect them.
(3)Connect the negative battery terminal.
(4)Erase the diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code 81 out put?

Go to Step 3.

The procedure is complete. It is assumed that diagnosis code 81 set as connector C-146 was engaged improperly.

STEP 3. Connector lock check: SRS-ECU connector C-146 and side-airbag module (LH) connector D-22 (M.U.T.-III diagnosis code).

(1)Disconnect the negative battery terminal.

(2)Disconnect connectors C-146 and D-22 and then reconnect them.
(3)Connect the negative battery terminal.
(4)Erase the diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code 81 out put?

Go to Step 4.

The procedure is complete. It is assumed that diagnosis code 81 set as connector C-146 or D-22 was engaged improperly.

STEP 4. 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 (LH) connector D-22.

(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-22 harness side connector by backprobing.
(5)Connect the negative battery terminal.
(6)Erase diagnosis code memory, and check the diagnosis code.

Q. Is diagnosis code 81 set?

Go to Step 5.

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

STEP 5. Resistance measurement at the SRS-ECU connector C-146.

(1)Disconnect SRS-ECU connector C-146.

(2)

danger

To prevents the air bag from deploying unintentionally, disconnect the side-airbag module (LH) connector D-22 to short the squib circuit.

Disconnect left hand side-airbag module (LH) connector D-22.

(3)

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 21, 22 and the short spring to release the short spring.

(4)

caution

Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.

Check for continuity between C-146 harness side connector terminals 21 and 22.
OK: Open circuit

Q. Is the check result normal?

Go to Step 6.

Repair the harness wires between SRS-ECU connector C-146 (terminal No.21 and 22) and side-airbag module (LH) connector D-22 (terminal No.1 and 2).

STEP 6. Check whether the diagnosis code is reset.

Q. Is diagnosis code 81 set?

	Replace the SRS-ECU (Refer to ).

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