![[Previous]](../../../buttons/fprev.png)
![[Next]](../../../buttons/fnext.png)
DTC B1C2A: Side-air
bag Module (LH) (Squib) System (Short Circuit between Squib Circuit Terminals)
| caution |
If DTC B1C2A is set in the SRS-ECU, always diagnose the CAN
bus lines.
|
CIRCUIT OPERATION
- The SRS-ECU judges how severe a collision is by detecting signals from the
side impact sensor installed on the lower side of the center pillar. If the impact is over a
predetermined level, the SRS-ECU sends an ignition signal. At this time, if the side collision
safing G-sensor is on, the SRS air bag will inflate.
- The ignition signal is input to the side-air bag module to inflate the side-air
bag.
DTC SET CONDITIONS
This DTC is set if there is abnormal resistance between the input terminals of the side-air
bag module (LH) (squib).
TROUBLESHOOTING HINTS
- Improper engaged connector or defective short spring*
- Short circuit between the side-air bag module (LH) (squib) circuit terminals
- Damaged connector(s)
- Malfunction of the SRS-ECU
| note |
*: The squib circuit connectors integrate a "short" spring (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) (Refer to  ).
Therefore, if connector C-36 or D-34 is damaged or improperly engaged, the short spring may
not be released when the connector is connected.
|
|
|
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
- MB991865: Dummy resistor
- MB991866: Resister harness
|
|
|
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
|
|
| caution |
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK"
(OFF) position before connecting or disconnecting scan tool MB991958.
|
(1)Connect scan tool MB991958. Refer to "How to connect the scan tool ."
(2)Connect scan tool MB991958 to the data link connector.
(3)Turn the ignition switch to "ON" position.
(4)Diagnose the CAN bus line.
Q.
Is the check result satisfactory?
 Go to Step 2.
 Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
|
|
|
STEP 2. Recheck for diagnostic trouble code.
|
|
|
Check again if the DTC is set.
|
|
|
(2)Turn the ignition switch to "ON" position.
|
|
|
(3)Check if the DTC is set.
|
|
|
(4)Turn the ignition switch to the "LOCK" (OFF) position.
|
|
|
Go to Step 3.
|
|
|
|
|
|
There is an intermittent malfunction such as poor engaged connector(s) or open
circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
|
|
|
|
|
|
STEP 3. Check SRS-ECU connector C-36 and side-air bag module (LH)
connector D-34.
|
|
|
(1)Disconnect the negative battery terminal.
|
|
(2)Disconnect the D-34 side-airbag module connector, and then reconnect them. Unlock the
connector by sliding the locking button to the direction of the arrow as shown in the figure,
and then disconnect the connector.
|
|
(3)While pushing the part "A" indicated in the figure of the harness side connector, turn
the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-36
SRS-ECU connector. Then connect the connector.
(4)Connect the negative battery terminal.
(5)Erase the diagnostic trouble code memory, and check the diagnostic trouble code.
Q.
Is DTC B1C2A out put?
Go to Step 4.
The procedure is complete. It is assumed that DTC B1C2A set because connector
C-36 or D-34 was engaged improperly.
|
|
|
STEP 4. Check the side-air bag module (LH).
|
|
|
(1)Disconnect the negative battery terminal.
|
|
(2)Unlock D-34 side-airbag module connector by sliding the locking button to the direction
of the arrow as shown in the figure, and then disconnect the connector.
|
|
(3)Connect special tool MB991865 to special tool MB991866.
(4)
| caution |
Do not insert a test probe into the terminal from its front side directly,
as the connector contact pressure may be weakened.
|
Insert special tool MB991866 into the D-34 harness side connector by backprobing.
(5)Connect the negative battery terminal.
(6)Erase diagnostic trouble code memory, and check the diagnostic trouble code.
Q.
Is DTC B1C2A set?
Go to Step 5.
Replace the front seatback (Refer to GROUP 52A, Front Seat Assembly ).
Then go to Step 7.
|
|
|
STEP 5. Check the side-air bag module (LH) circuit. Measure the resistance
at the SRS-ECU connector C-36.
|
|
|
(1)Disconnect the negative battery terminal.
|
|
(2)While pushing the part "A" indicated in the figure of the harness side connector, turn
the lock lever to the direction of the arrow to release the lock lever, and disconnect the C-36
SRS-ECU connector.
|
|
(3)
| danger |
To prevent the air bag from deploying unintentionally, disconnect
the side-air bag module (LH) connector D-34 to short the squib circuit.
|
Unlock D-34 side-airbag module connector by sliding the locking button to the direction
of the arrow as shown in the figure, and then disconnect the connector.
|
|
(4)
| caution |
Insert an insulator such as a cable tie to a depth of 4mm (0.16 inch) or more, otherwise
the short spring will not be released.
|
Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between
terminals 31, 32 and the short spring to release the short spring.
|
|
(5)Check for continuity between C-36 harness side connector terminals 31 and 32.
It should be an open circuit.
Q.
Is it open circuit?
Erase the diagnostic trouble code memory, and check the diagnostic trouble code.
If DTC B1C2A sets, replace the SRS-ECU (Refer to ). Then go to Step
7.
Go to Step 6.
|
|
|
STEP 6. Check the harness wires for short circuit between SRS-ECU
connector C-36 (terminal No.31 and 32) and side-air bag module (LH) connector D-34 (terminal
No.2 and 1).
|
|
|
Q.
Is the check result normal?
|
|
|
Go to Step 7.
|
|
|
|
|
|
Repair the harness wires between SRS-ECU connector C-36 and side-air bag module
(LH) connector D-34. Then go to Step 7.
|
|
|
|
|
|
STEP 7. Recheck for diagnostic trouble code.
|
|
|
Check again if the DTC is set.
|
|
|
(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.
|
|
|
Return to Step 1.
|
|
|
|
|
|
The procedure is complete.
|
|
|
|
)
)
)
)
)
)
)
)
)