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)
- MB991223 (MB991222): Harness set (Probe)

STEP 1. Check the side impact sensor (LH) line at the SRS-ECU connector C-45 by backprobing.
1. Do disconnect the side impact sensor (LH) connector D-20.
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-45 and side impact sensor (LH) connector D-20.

NOTE: After inspecting intermediate connector D-23, inspect the wire. If the intermediate connector D-23 is damaged, repair or rep lace it. Refer to Harness Connector Inspection. Then go to Step 3. If harness wires are in good condition, go to step 3. If any harness wires between SRS-ECU connector C-45 and side impact sensor (LH) connector D-20 are damaged, repair them or install the sensor cable. Then go to Step 3.

Q: Are the harness wires between SRS-ECU connector C-45 and side impact sensor (LH) connector D-20 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.)