Code No.B1453: Curtain air bag module (LH) (squib) system (short-circuited to the power supply)
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If diagnosis code B1453 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 air bag safing G-sensor. If the impact is over a predetermined level, the SRS-ECU outputs an ignition signal. At this time, if the side air bag 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 power supply.
PROBABLE CAUSES
- Damaged wiring harnesses or connectors
- Short to the power supply in the curtain air bag module (LH) (squib) harness
- Malfunction of the SRS-ECU
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STEP 1. M.U.T.-III CAN bus diagnostics.
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| warning |
Since the radiator fan rotates during CAN bus line diagnostics, make sure that no one is servicing the engine compartment before diagnosing the CAN bus line. Since the CAN communication stops when diagnosing the CAN bus line, the ETACS-ECU detects the time-out of the engine-ECU, and activates the radiator fan to prevent overheating as fail-safe.
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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 54C, Troubleshooting - Can Bus Diagnosis Table  ).
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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)Turn the ignition switch to the "ON" position.
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(3)Check if the diagnosis code is set.
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(4)Turn the ignition switch to the "LOCK" (OFF) position.
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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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(2)Use a flat-tipped screwdriver to pull out forward and unlock the locking button of the harness side connector, and then disconnect curtain air bag module (LH) connector C-08.
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(3)Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991884).
(4)Connect special tool resistor harness (MB991884) to the C-08 harness side connector.
(5)Connect the negative battery terminal.
(6)Erase diagnosis code memory, and check the diagnosis code.
Q.
Is diagnosis code B1453 set?
Go to Step 4.
Replace the curtain air bag module (LH) (Refer to ).
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STEP 4. Voltage measurement at the SRS-ECU connector B-109.
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(1)Disconnect the negative battery terminal.
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(2)Disconnect SRS-ECU connector B-109.
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To prevent the air bag from deploying unintentionally, disconnect the curtain air bag module (LH) connector C-08 to short the squib circuit.
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(3) Use a flat-tipped screwdriver to pull out forward and unlock the locking button of the harness side connector, and then disconnect curtain air bag module (LH) connector C-08.
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(4)
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Insert an insulator such as a cable tie to a depth of 4mm or more, otherwise the short spring will not be released.
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Insert a cable tie [3 mm wide, 0.5 mm thick] between terminals 33 and the short spring to release the short spring.
(5)Connect the negative battery terminal.
(6)Turn the ignition switch to the "ON" position.
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(7)Voltage measurement between B-109 harness side connector terminals 9, 10 and body earth.
OK: 1 V or less
Q.
Is the check result normal?
Go to Step 5.
Repair the harness wire between SRS-ECU connector B-109 (terminal No.9 and 10) and curtain air bag module (LH) connector C-08 (terminal No.1 and 2).
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STEP 5. Check whether the diagnosis code is reset.
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Q.
Is diagnosis code B1453 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 Cope with Intermittent Malfunction ).
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