Code No.91: Side impact sensor (LH) voltage error

OPERATION

The side impact sensor includes an analog G sensor and CPU, etc. The CPU monitors the analog G sensor output signal. If the CPU judges that the side-airbags should be deployed, it sends a fire signal to the SRS-ECU to deploy the side-airbags. Besides that, the CPU diagnoses the internal components of the side impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnosis code.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code will set when the power supply voltage to the side impact sensor (LH) remains less than a predetermined value for 5 seconds. However, if the system returns to normal condition, code number 91 will be erased automatically and the SRS warning lamp will go out.

PROBABLE CAUSES

Damaged wiring harness or connectors
Malfunction of the side-airbag module (LH)
Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the harness wires for open circuit or short circuit between SRS-ECU connector C-146 (terminal No.34 and 36) and side impact sensor (LH) connector D-18 (terminal No.1 and 2).

Q. Is the check result normal?

Go to Step 2.

Repair the harness wires between SRS-ECU connector C-146 (terminal No.34 and 36) and side impact sensor (LH) connector D-18 (terminal No.1 and 2).

STEP 2. Check the side impact sensor (LH) (M.U.T.-III diagnosis code).

(1)Disconnect the negative battery terminal.

(2)Replace the side impact sensor (LH) with the side impact sensor RH).

(3)Connect the negative battery terminal.

(4)Erase diagnosis code from memory, and check the diagnosis code.

Q. Is diagnosis code 91 set?

	Replace the SRS-ECU (Refer to ).

	Replace the side impact sensor (LH) with a new one (Refer to ). Go to Step 3.

STEP 3. Check whether the diagnosis code is reset.

Q. Is diagnosis code 91 set?

	Replace the SRS-ECU (Refer to ).

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