DTC 81
Left Hand Side-airbag Module (Squib) System Fault 1Left Hand Side-airbag (Squib) Circuit:
CIRCUIT OPERATION
- The SRS-ECU judges how severe a collision is by detecting signals from the left and right side impact sensors 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.
- The ignition signal is input to the air bag module to inflate the air bag.
DTC SET CONDITIONS
- These DTC are output if there is abnormal resistance between the input terminals of the side-airbag module (LH) (squib). The most likely causes for this code to be set are shown in the table.
TROUBLESHOOTING HINTS
- Improper engaged connector or defective short bar*
- Short between the side-airbag module (LH) (squib) circuit terminals
- Damaged connector(s)
- Malfunction of the SRS-ECU
NOTE: *: The squib circuit connectors integrate a "short" bar (which prevents the air bag from deploying unintentionally due to static electricity by shorting the positive wire to the ground wire in the squib circuit when the connectors are disconnected). Therefore, if connector C-74 or D-15 is damaged or improperly engaged, the short bar may not be released when the connector is connected.
DIAGNOSIS
Required Special Tools:
- MB991502: Scan Tool (MUT-II)
- MB991865: Dummy resister
- MB991866: Resister harness
STEP 1. Check the side-airbag module line using the scan tool, MB991865 dummy resistor and MB991866 resistor harness.
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 any of DTC 81, 82, 85 or 86 output?
YES: :Go to Step 2.
NO: Replace the seat back assembly of the front seat (LH). Then go to Step 3.
STEP 2. Check the harness wires between SRS-ECU connector C-74 and side air bag module (LH) connector D-15.
Q: Are the harness wires between SRS-ECU connector C-74 and side air bag module (LH) connector D-15 in good condition?
YES: Go to Step 3.
NO: Repair them. Then go to Step 3.
STEP 3. Check for DTC.
Q: Is any of DTC 81, 82, 85 or 86 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.)