DTC 69

DTC 69: Passenger's (Front) Seat Belt Pre-Tensioner (Squib) System Fault for Ground Circuit (Short-Circuit to Ground)

Passenger's (Front) Seat Belt Pre-tensioner (Squib) part 1:

Passenger's (Front) Seat Belt Pre-tensioner (Squib) part 2:

CIRCUIT OPERATION
The SRS-ECU judges how severe a collision is by detecting signals from the front impact sensors and the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU outputs an ignition signal. At this time, if the front air bag safing G-sensor is on, the pre-tensioner will deploy.

DTC SET CONDITIONS
This DTC is set if there is abnormal resistance between the input terminals of the passenger's seat belt pre-tensioner (squib).

TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Short to the ground in the passenger's seat belt pre-tensioner (squib) harness
- Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991911: M.U.T.-III Main Harness B
- MB991865: Dummy resister
- MB991866: Resister harness (For Pre-tensioner)

STEP 1. Check the passenger's seat belt pre-tensioner (Using scan tool MB991958, read the diagnostic trouble code).







1. Disconnect the negative battery terminal.
2. Disconnect driver's seat belt pre-tensioner connector D-03. Use a flat-tipped screwdriver to unlock the locking button at the harness side connector by withdrawing it toward you in two stages, and then disconnect the connector.




3. Connect special tool MB991865 to special tool MB991884.
4. Connect special tool MB991884 to the D-03 harness connector.
5. Connect the negative battery terminal.
6. Erase the diagnostic trouble code memory, and then check the diagnostic trouble code.

Q: Is DTC 69 set?

YES: Go to Step 2.

NO: Replace the passenger's seat belt pre-tensioner. Then go to Step 3.

STEP 2. Check the passenger's seat belt pre-tensioner circuit at the SRS-ECU connector C-13.




1. Disconnect SRS-ECU connector C-13.







2. Disconnect driver's seat belt pre-tensioner connector D-03. Use a flat-tipped screwdriver to unlock the locking button at the harness side connector by withdrawing it toward you in two stages, and then disconnect the connector.

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




3. Check for continuity between C-13 harness connector terminals 27, 28 and body ground. It should be open circuit.

Q: Does continuity exist?

YES: Go to Step 3.

NO: Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC 69 sets, replace the SRS-ECU. Then go to Step 4.










STEP 3. Check harness wires for short circuit to ground between SRS-ECU connector C-13 (terminal No.27 and 28) and passenger's seat belt pre-tensioner connector D-03 (terminal No.1 and 2).

NOTE: After inspecting intermediate connector C-112 inspect the wiring harness.

If the intermediate connector C-112 is damaged, repair or replace it. Refer to Harness Connector Inspection.

Q: Are the harness wires between SRS-ECU connector C-13 (terminal No.27 and 28) and passenger's seat belt pre-tensioner connector D-03 (terminal No.1 and 2) in good condition?

YES: Go to Step 4.

NO: Repair the harness wires between SRS-ECU connector C-13 and passenger's seat belt pre-tensioner connector D-03. Then go to Step 4.

STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set.




1. Erase the DTC.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is DTC 69 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).