DTC 91

Left Hand Side Impact Sensor Power Supply Circuit System

Side Impact Sensor (LH) Power Supply Circuit:

CIRCUIT OPERATION
The SRS-ECU judges how severe a collision is by detecting signals from the side impact sensor and the analog G-sensor. If the impact is over a predetermined level, the SRS-ECU outputs an ignition signal. At this time, if the safing G-sensor is on, the SRS air bag will inflate.

DTC SET CONDITIONS
This DTC is output if a poor connection at the SRS-ECU is detected. However, if the vehicle condition returns to normal, DTC number 91 will be automatically erased, and the SRS warning light will go out.

TROUBLESHOOTING HINTS
- Damaged connectors
- Malfunction of the side impact sensor (LH)
- Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:
MB991502: Scan Tool (MUT-II)

STEP 1. Check the side impact sensor (LH) line at the side impact sensor connector D-12 by backprobing.
1. Do disconnect the side impact sensor (LH) connector D-12.
2. Connect the negative battery terminal.
3. Turn the ignition switch to the "ON" position.




4. Measure the voltage between terminal 1 and ground by backprobing.
- Voltage should be 9 volts or more




5. Check the continuity between terminal 2 and ground by backprobing.
- Should be less than 2 ohm.

Q: Does the voltage meet the specifications or is the resistance less than 2 ohm?

YES: Replace the side impact sensor (LH). Then go to Step 3.

NO: Go to Step 2.







STEP 2. Check the harness wires between SRS-ECU connector C-74 and side impact sensor (LH) connector D-12.

Q: Are the harness wires between SRS-ECU connector C-74 and side impact sensor (LH) connector D-12 in good condition?

YES: Go to Step 3.

NO: Repair them. Then go to Step 3.

STEP 3. Check DTC.

Q: Is DTC 91 output?

YES: Replace the SRS-ECU.

NO: This diagnosis is complete. (If no malfunctions are not found in all steps, an intermittent malfunction is suspected. Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction.)