DTC 72

DTC 72: Right Hand Side-Airbag Module (Squib) System Fault 2 (Open in 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 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 (RH) (squib).

TROUBLESHOOTING HINTS
- Open circuit in the side-airbag module (RH) (squib) circuit
- Improper connector contact
- Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface
- MB991827: MUT-III USB Cable
- MB991911: MUT-III Main Harness B
- MB991865: Dummy resister
- MB991866: Resister harness

STEP 1. Check the side-airbag module (RH) (Using scan tool MB991958, read the diagnostic trouble code).




1. Disconnect the negative battery terminal.
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. Disconnect the side-airbag module (RH) connector D-19, and insert special tool MB991866 into the harness side connector by backprobing.
4. Connect the negative battery terminal.
5. Erase the DTC memory, and then recheck the DTC.

Q: Is DTC 72 set?

YES: Go to Step 2.

NO: Replace the seat back assembly of the front seat (RH). Refer to Front Seat. Then go to Step 3.

STEP 2. Check the harness for open circuit between SRS-ECU and the side-air bag module (RH).







1. Disconnect SRS-ECU connector C-74 and side-air bag module (RH) connector D-19, and 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.




2. Check for continuity between the following terminals.
- SRS-ECU connector C-74 (terminal No.23) and the side-air bag module (RH) connector D-19 (terminal No.2)
- SRS-ECU connector C-74 (terminal No.24) and the side-air bag module (RH) connector D-19 (terminal No.1)
- Should be less than 2 ohms.

Q: Does continuity exist?

YES: Erase the DTC memory, and recheck if any DTC sets. If DTC 72 sets, replace the SRS-ECU. Then go to Step 3.

NO: Repair the harness wires between SRS-ECU connector C-74 and side-airbag module (RH) connector D-19. Then go to Step 3.

STEP 3. Recheck for diagnostic trouble code.

Q: Is DTC 72 set?

YES: Return to Step 1.

NO: The procedure is complete (If no malfunctions are found in all steps, an intermittent malfunction is suspected. Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction).