Code No. B1443 Right front curtain air bag module (squib) system (shorted
to squib circuit power supply) <Vehicles with rear curtain air
bag>
caution |
If diagnosis code B1443 is set in the SRS-ECU, be sure
to diagnose the CAN bus line.
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OPERATION
In case of side collision, when the impact exceeding the
threshold is applied to the vehicle, and when the impact is simultaneously
detected (turned ON) by the side impact sensor as well as by the analogue
G-sensor in SRS-ECU, the electric current is supplied from SRS-ECU to the
front curtain air bag module (squib) of impacted side.
TROUBLE JUDGEMENT
The code is set when the SRS-ECU front curtain
air bag module (squib) is shorted to power supply.
PROBABLE CAUSES
- Damaged wiring harness and connector
- Front curtain air bag module (squib) harness shorted to power
supply
- Malfunction of SRS-ECU
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STEP 1. M.U.T.-III CAN bus diagnostic.
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Use 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 54C - Troubleshooting ).
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STEP 2. Check whether the diagnosis code is set again.
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(1)Connect the negative battery terminal.
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(2)After erasing the diagnosis code memory, check the
diagnosis code again.
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(3)Disconnect the negative battery terminal.
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Q.
Is diagnosis code No. B1443 set?
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Go to Step 3.
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Intermittent malfunction (Refer to
GROUP 00 - How to Use Troubleshooting/Inspection Service Points
- How to Cope with Intermittent Malfunction).
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STEP 3. Diagnosis check by dummy resistor connection
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(1)Check that the negative battery terminal is disconnected.
If connected, disconnect the negative battery terminal.
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![](../../../img/52/AC904706AC00ENG.png)
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(2)Use the flat-tipped screwdriver to pull out
the locking button of right front curtain air bag module connector to the
direction of the arrow. After releasing the lock, disconnect the connector.
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![](../../../img/52/AC301553DQ00ENG.png)
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(3)Connect the dummy resistor (Special tool:
MB991865) to the resistor harness (Special tool: MB991884). (4)Connect
the resistor harness (special tool) to right front curtain air bag module
(front) connector. (5)Connect the negative battery terminal. (6)After
erasing the diagnosis code memory, check the diagnosis code
again. (7)Disconnect the negative battery terminal.
Q.
Is diagnosis code No. B1443 set?
Go to step 4.
Replace the right front curtain air
bag module.
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STEP 4. Voltage measurement at the SRS-ECU connector.
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(1)Check that the negative battery terminal is disconnected.
If the negative battery terminal is connected, disconnect it.
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![](../../../img/52/AC905015AC00ENG.png)
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(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. After disconnect the SRS-ECU
connector.
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![](../../../img/52/AC904706AC00ENG.png)
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(3)
danger |
To release SRS-ECU wiring harness side connector
short spring in the following operations, disconnect front curtain air
bag module connector in advance, and keep the squib circuit
shorted.
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Use the flat-tipped screwdriver to pull out the locking button of
right front curtain air bag module connector to the direction of the arrow.
After releasing the lock, disconnect the connector.
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![](../../../img/52/AC905150BJ00ENG.png)
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(4)
caution |
The short spring may not be released due to the
insufficient insertion. Therefore, insert the insulator for 4 mm or
more.
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Insert an insulator (width: 3 mm, thickness: 0.5 mm) such as cable
tie between the CRS-, CRS+ line and the short spring, and release the
short spring. (5)Connect the negative battery terminal. (6)Ignition
switch: "ON" (7)Measure the voltage between the SRS-ECU wiring harness
side connector CRS-, CRS+ line and the body earth. OK: 1
V or less (8)Disconnect the negative battery terminal.
Q.
Is the check result normal?
Go to Step 5.
Repair the wiring
harness.
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STEP 5. Check whether the diagnosis code is set again.
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Q.
Is diagnosis code No. B1443 set?
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Replace SRS-ECU.
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Intermittent Malfunction (Refer to
GROUP 00 - How to Use Troubleshooting/Inspection Service Points
- How to Cope with Intermittent Malfunction).
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