DTC 91

Side Impact Sensor (LH) Power Supply Circuit System

Side Impact Sensor (LH) Power Supply Circuit:

CIRCUIT 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 an ignition 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 diagnostic trouble code.

DTC SET CONDITIONS
This DTC will set when the power supply voltage to the side impact sensor (LH) remains less than a predetermined value for five seconds. However, if the vehicle condition returns to normal, the DTC 91 will be automatically erased, and the SRS warning light will go out.

TROUBLESHOOTING HINTS
- Damaged wiring harness or connectors
- Malfunction of the side air bag module (LH) (squib)
- Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:
- MB991502: Scan Tool (MUT-II)
- MB991223 (MB991222): Harness Set (Probe)

STEP 1. Check the side Impact sensor (LH) power supply circuit at the side impact sensor (LH) connector D-22.




1. Disconnect the side impact sensor (LH) connector D-22, and measure at the wiring harness side.
2. Connect the negative battery terminal.
3. Turn the ignition switch to the "ON" position.

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




4. Measure the voltage between the D-22 harness side connector terminal 2 and the ground.
Voltage should be 9 volts or more

Q: Is the measured voltage within the specified range?

YES: Replace the side impact sensor (LH). Then go to Step 3.
NO: Go to Step 2.







STEP 2. Check the harness wires for open circuit or short circuit between the SRS-ECU connector C-145 (terminal No.34 and 36) and the side impact sensor (LH) connector D-22 (terminal No.1 and 2).

Q: Are the harness wires between the SRS-ECU connector C-145 (terminal No.34 and 36) and the side impact sensor (LH) connector D-22 (terminal No.1 and 2) in good condition?

YES: Erase the DTC memory, and recheck if any DTC sets. If DTC 91 sets, replace the SRS-ECU. Then go to Step 3.
NO: Repair the harness wires between the SRS-ECU connector C-145 and the side impact sensor (LH) connector D-22. Then go to Step 3.

STEP 3. Check for DTC.

Q: Is DTC 91 set?

YES: Return to Step 1.
NO: The procedure is complete. (If no malfunctions are not found in all steps, an intermittent malfunction is suspected. Refer to INTRODUCTION, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction.)