DTC 85

Left Hand Side-Airbag Module (Squib) System Fault Power Supply Circuit (Short-Circuit To Power Supply)

Side Air Bag Module (LH) (Squib) Circuit:

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 air bag will inflate.
- The ignition signal is input to the air bag module to inflate the air bag.

DTC SET CONDITIONS
- This DTC is set if there is abnormal resistance between the input terminals of the side-airbag module (LH) (squib).

TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Short to the power supply in the left hand side-airbag module (squib) harness
- Malfunction of the SRS-ECU

Required Special Tool:
- MB991502: Scan Tool (MUT-II)
- MB991865: Dummy resister
- MB991866: Resister harness

STEP 1. Check the side-airbag module (LH).




1. Connect special tool MB991865 to special tool MB991866.

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

2. Disconnect the side-airbag module (LH) connector D-15, and insert special tool MB991866 into the harness side connector by backprobing.
3. Connect the negative battery terminal.
4. Erase the DTC memory, and then recheck the DTC.

Q: Is DTC 85 output?

YES: Go to Step 2.

NO: Replace the seat back assembly of the front seat (LH). Refer to Front Seat. Then go to Step 4.

STEP 2. Check the harness for short circuit to power supply between the SRS-ECU and the side-airbag module (LH).










1. Disconnect SRS-ECU connector C-74.
2. Disconnect left hand side-airbag module connector D-15.
3. Turn the ignition switch to the "ON" position.
4. Measure at the wiring harness side.

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

5. Measure the voltage between terminals 21, 22 and body ground.
- Voltage should be 0 volt.

Q: Is the voltage normal?

YES: Erase the DTC memory, and recheck if any DTC sets. If DTC 85 sets, replace the SRS-ECU. Then go to Step 4.

NO: Go to Step 3.







STEP 3. Check the harness wires for short circuit to power supply between SRS-ECU connector C-74 (terminal No.21 and 22) and side-airbag module (LH) connector D-15 (terminal No.1 and 2).

Q: Are the harness wires between SRS-ECU connector C-74 (terminal No.21 and 22) and side-airbag module (LH) connector D-15 (terminal No.1 and 2) in good condition?

YES: Go to Step 4.

NO: Repair the harness wires between SRS-ECU connector C-74 and side-airbag module (LH) connector D-15. Then go to Step 4.

STEP 4. Check the DTC.

Q: Is DTC 85 output?

YES: Return to Step 1.

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.)