Code No.B1437: Side impact sensor (LH) voltage error
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If diagnosis code B1437 is set in the SRS-ECU, always diagnose the CAN main bus line.
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OPERATION
The side impact sensor includes an analogue G-sensor. The side impact sensors transmit coded acceleration data to SRS-ECU. The SRS-ECU then determines whether to operate the side-airbag module, curtain air bag module and seat belt pretensioners, and then outputs an ignition signal when necessary. The side impact sensor also diagnoses itself, and sends a diagnosis code to the SRS-ECU if a problem occurs.
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if the power supply voltage of the side impact sensor (LH) drops below the rated value for a continuous period of 5 seconds or more.
PROBABLE CAUSES
- Damaged wiring harnesses or connectors
- Malfunction of the side-airbag module (LH) (squib)
- 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 check the CAN bus lines.
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Q.
Is the CAN bus line found to be 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 harness wires for open circuit and short circuit between SRS-ECU connector B-109 (terminal No.40 and 41) and side impact sensor (LH) connector C-19 (terminal No.2 and 1).
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Q.
Is the check result normal?
Go to Step 4.
Repair the harness wires between SRS-ECU connector B-109 and side impact sensor (LH) connector C-19.
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STEP 4. Check the impact sensor (LH) (M.U.T.-III diagnosis code).
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(1)Disconnect the negative battery terminal.
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(2)Temporarily replace the side impact sensor (LH) with the side impact sensor (RH).
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(3)Connect the negative battery terminal.
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(4)Erase diagnosis code from memory, and check the diagnosis code.
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Q.
Is diagnosis code B1427 set?
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Replace the side impact sensor (LH) with a new one (Refer to ).
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Go to Step 5.
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STEP 5. Check whether the diagnosis code is reset.
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Q.
Is diagnosis code B1437 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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