Code No.B1452: Curtain air bag module (squib) (LH) system
(short-circuited to the earth)
![](../../../img/52/W4X52E011A00ENG.png)
caution |
If diagnosis code B1452 is set in the
SRS-ECU, always diagnose the CAN main bus line.
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OPERATION
The SRS-ECU judges how severe a collision is by
detecting signals from the side impact sensors and the side-airbag
safing G-sensor. 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 curtain air bag module will deploy.
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if
the curtain air bag module squib (LH) wire(s) are short-circuited to the
earth.
PROBABLE CAUSES
- Damaged wiring harnesses or connectors
- Short to the earth in the curtain air bag module (squib) (LH)
harness
- Malfunction of the SRS-ECU
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STEP 1. M.U.T.-III CAN bus diagnostics
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Use the M.U.T.-III to diagnose the
CAN bus lines.
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Q.
Is the check result normal?
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Go to Step 2
.
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Repair the CAN bus
line (Refer to GROUP 54F, Diagnosis ).
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STEP 2. Check whether the diagnosis code is
reset.
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Check again if the diagnosis code
is set.
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(1)Erase the diagnosis code.
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(2)Ignition: LOCK (OFF) position to ON
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(3)On completion, check that the diagnosis code is
not reset.
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Q.
Is the diagnosis code set?
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Go to Step 3
.
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There is an
intermittent malfunction such as poor engaged connector(s)
or open circuit (Refer to GROUP 00, How to Cope with
Intermittent Malfunction ).
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STEP 3. Check the curtain air bag module (LH)
(M.U.T.-III diagnosis code).
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(1)Disconnect the negative battery
terminal.
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![](../../../img/52/AC302576AE00ENG.png)
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(2)Disconnect the intermediate
connector G-22 (connection between rear floor harness and
floor harness).
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![](../../../img/52/AC006042CA00ENG.png)
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(3)Connect special tool dummy
resistor (MB991865) to special tool resistor harness
(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.
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Insert special tool resistor harness probe into
floor harness side connector G-22 by
backprobing. (5)Connect the negative battery
terminal. (6)Erase diagnosis code memory, and check the
diagnosis code.
Q.
Is diagnosis code B1452 set?
Go to Step 4
.
Go to Step 5
.
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STEP 4. Check the curtain air bag module (LH) circuit.
Resistance measurement at the SRS-ECU connector
C-120.
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![](../../../img/52/AC311438AE00ENG.png)
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(1)Disconnect SRS-ECU connector
C-120.
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![](../../../img/52/AC302576AE00ENG.png)
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(2)Disconnect the intermediate
connector G-22 (connection between rear floor harness and
floor harness).
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![](../../../img/52/AC301563AC00ENG.png)
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(3)
caution |
Do not insert a test probe
into the terminal from its front side directly
as the connector contact pressure may be
weakened.
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Resistance measurement between C-120 harness side
connector terminals 5, 6 and body earth. OK:
Open circuit
Q.
Is the check result normal?
Go to Step 6
.
Repair the
harness wire between SRS-ECU connector C-120 (terminal No.5
and 6) and intermediate connector G-22 (floor harness side,
terminal No.1 and 2).
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STEP 5. Check the curtain air bag module (LH) circuit.
Resistance measurement at the intermediate connector
G-22.
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![](../../../img/52/AC302576AE00ENG.png)
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(1)Disconnect the intermediate
connector G-22 (connection between rear floor harness and
floor harness).
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![](../../../img/52/AC303223AC00ENG.png)
![](../../../img/52/AC208384AN00ENG.png)
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(2)Disconnect curtain air bag
module (LH) connector G-01. 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.
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![](../../../img/52/AC303710AC00ENG.png)
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(3)
caution |
Do not insert a test probe
into the terminal from its front side directly
as the connector contact pressure may be
weakened.
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Resistance measurement between G-22 rear floor
harness side connector terminals 1, 2 and body
earth. OK: Open circuit
Q.
Is the check result normal?
Replace the curtain
air bag module (LH) (Refer to ).
Repair the
harness wire between intermediate connector G-22 (terminal
No.1 and 2) and curtain air bag module (LH) connector G-01
(terminal No.1 and 2).
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STEP 6. Check whether the diagnosis code is
reset.
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Q.
Is diagnosis code B1452 set?
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Replace the SRS-ECU
(Refer to ).
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An intermittent
malfunction is suspected (Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points ).
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