B1413

DTC B1413: Passenger's (Front) Air Bag Module (1st Squib) System Fault for Ground Circuit (Short-Circuited to Ground)

Passenger's (Front) Air Bag Module (1st Squib And 2nd Squib) Circuit:

CAUTION: If DTC B1413 <1st squib> or B1493 <2nd squib> is set in the SRS-ECU, always diagnose the CAN main bus line.

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 sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
- The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

DTC SET CONDITIONS
This DTC is set if there is abnormal resistance between the input terminals of the passenger's air bag module (squib). However, if no DTC resets, the SRS warning light will be switched off (DTC will be retained).

TROUBLESHOOTING HINTS
- Damaged harness wires and connectors
- Short to the ground in the passenger's air bag module (squib) harness
- Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A (Vehicles with CAN Communication)
- MB991865: Dummy resistor
- MB991866: Resister harness

STEP 1. 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 the DTC set?

YES: Go to Step 2.

NO: There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to How to Cope with Intermittent Malfunction).

STEP 2. Check the passenger's air bag module. (Using scan tool MB991958, read the diagnostic trouble code.)




1. Disconnect the negative battery terminal.
2. Disconnect the passenger's air bag module connector C-09.




3. Slide the outer housing of the clock spring side of passenger's air bag module connector C-09 in the arrow direction shown, and disconnect the connector.




4. 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.

5. Insert special tool MB991866 into the harness side connector C-09 (terminal No.1 and 2 <1st squib> or terminal No3. and 4 <2nd squib>) by backprobing.
6. Connect the negative battery terminal.

CAUTION: Always DTC B1491 is set when checking DTC B1413. This is because the second side terminal is isolated when checking it, DTC B1491 is set but this is not a fault. In addition, always DTC B1411 is set when checking DTC B1493 because the first side terminal is isolated.

7. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

Q: Is DTC B1413 <1st squib> B1493 <2nd squib> set?

YES: Go to Step 3.

NO: Replace the passenger's air bag module. Then go to Step 5.

STEP 3. Check the passenger's air bag module circuit. Measure the resistance at the SRS-ECU connector C-115.




1. Disconnect SRS-ECU connector C-115.

DANGER: prevent the air bag from deploying unintentionally, disconnect the passenger's air bag module connector C-09 to short the squib circuit.




2. Unclip passenger's air bag module connector C-09.
3. Disconnect the passenger's air bag module connector C-09.

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 C-115 harness side connector terminals 27 and 28 <1st squib> or 30 and 31 <2nd squib>, and body ground.

It should be open circuit.

Q: Does continuity exist?

YES: Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1413 <1st squib> B1493 <2nd squib> sets, replace the SRS-ECU. Then go to Step 5.

NO: Go to Step 4.







STEP 4. Check the harness wires for short circuit to ground between SRS-ECU connector C-115 (terminal No.27 and 28 <1st squib> or terminal No.30 and 31 <2nd squib>) and passenger's air bag module connector C-09 (terminal No.1 and 2 <1st squib> or terminal 4. and 3 <2nd squib>).

Q: Are the harness wires between SRS-ECU connector C-115 (terminal No.27 and 28 <1st squib> or terminal No.30 and 31 <2nd squib>) and passenger's air bag module connector C-09 (terminal No.1 and 2 <1st squib> or terminal 4. and 3 <2nd squib>) in good condition?

YES: Go to Step 5.

NO: Replace the harness wires between SRS-ECU connector C-115 and passenger's air bag module connector C-09. Then go to Step 5.

STEP 5. 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 B1413 <1st squib> B1493 <2nd squib> set?

YES: Return to Step 1.

NO: The procedure is complete.