DTC 71

Side-Airbag Module (RH) (Squib) System Fault 1 (Short Circuit between Terminals of the Squib Circuit)

Side-airbag Module (RH) (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 side-airbag will inflate.
- The ignition signal is input to the side-airbag module to inflate the side-airbag.

DTC SET CONDITIONS
This DTC is set if a short circuit is detected between the terminals of the side-airbag module (RH) (squib). However, if the vehicle condition returns to normal, the SRS warning light will go out, but the DTC will be retained.

TROUBLESHOOTING HINTS
- Improper engaged connector or defective short bar*
- Short circuit between the side-airbag module (RH) (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 the connector C-145 or D-24 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 Resistor
- MB991866: Resistor Harness
- MB991223 (MB991222): Harness Set (Probe)

STEP 1. Check the DTC.

Q: Is DTC 34 set?

YES: Go to Step 2.
NO: Go to Step 3.




STEP 2. Check the SRS-ECU connector C-145.

Q: Is the connector correctly engaged?

YES: Go to Step 3.
NO: Engage the connector correctly. Then go to Step 7.

STEP 3. Check the SRS-ECU connector C-145 and the side-airbag module (RH) connector D-24.







1. Disconnect the connectors C-145 and D-24, and then reconnect them.
2. Connect the negative battery terminal.
3. Erase the DTC memory, and then recheck the DTC.

Q: Is DTC 71 set?

YES: Go to Step 4.
NO: The procedure is complete. It is assumed that DTC 71 set as the connector C-145 or D-24 was engaged improperly.

STEP 4. Check the side-airbag module (RH).




1. Disconnect the side-airbag module (RH) connector D-24.




2. 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.

3. Insert special tool MB991866 into the D-24 harness side connector by backprobing.
4. Connect the negative battery terminal.
5. Erase the DTC memory, and then recheck the DTC.

Q: Is DTC 71 set?

YES: Go to Step 5.
NO: Replace the seatback assembly of the front seat (RH). (Refer to Front Seat Assembly.) Then go to Step 7.

STEP 5. Check the side-airbag module (RH) circuit at the
SRS-ECU connector C-145.




1. Disconnect the SRS-ECU connector C-145.

DANGER: To prevent the side-airbag from deploying unintentionally, disconnect the side-airbag module (RH) connector D-24 to short the squib circuit.




2. Disconnect the side-airbag module (RH) connector D-24.

CAUTION: Insert an insulator such as a cable tie to a depth of 4mm (0.16 inch) or more, otherwise the short bar will not be released.




3. Insert a cable tie [3mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between the terminals 23, 24 and the short bar to release the short bar.




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

(4) Check for continuity between the C-145 harness side connector terminals 23 and 24.

It should be open circuit.

Q: Does continuity exist?

YES: Erase the DTC memory, and recheck if any DTC sets. If DTC 71 sets, replace the SRS-ECU. (Refer to P.8M-149.) Then go to Step 7.

NO: Go to Step6.









STEP 6. Check the harness wires for short circuit between the SRS-ECU connector C-145 (terminal No.23 and 24) and the side-airbag module (RH) connector D-24 (terminal No.1 and 2).

Q: Are the harness wires between the SRS-ECU connector C-145 (terminal No.23 and 24) and the side-airbag module (RH) connector D-24 (terminal No.1 and 2) in good condition?

YES: Go to Step 7.

NO: Repair the harness wires between the SRS-ECU connector C-145 and the side-airbag module (RH) connector D-24. Then go to Step 7.

STEP 7. Check for DTC.

Q: Is DTC 71 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 P.-6.)