Code No.B1438
Side impact sensor (LH) communication error
Code No.B1439 Side impact sensor (LH) communication
impossible
caution |
If the diagnosis code B1438
or B1439 is set to SRS-ECU, be sure to diagnose the CAN bus line.
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OPERATION
The side impact sensor transmits acceleration data to the SRS-ECU. The SRS-ECU then determines.
if the side and/or curtain air bags should be inflated, and then sends an ignition
signal. The side impact sensor also diagnoses itself, and sends a diagnosis code to the SRS-ECU
if a problem occurs.
DIAGNOSIS CODE SET CONDITIONS
The diagnosis code is set if the communication between the left side impact sensor and
SRS-ECU is abnormal (No. B1438), or impossible (No. B1439).
PROBABLE CAUSES
- Damaged wiring harnesses or connectors
- Malfunction of the side impact sensor (LH)
- 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 54C, 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 side impact sensor (LH).
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(1)Disconnect the negative battery terminal.
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(2)Alternate the side impact sensor (LH) and the side impact sensor (RH), and then
install the alternated sensor.
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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 B1438 or B1439 set?
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Replace the side impact sensor (LH) with a new one (Refer to ).
Go to Step 5.
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Go to Step 4.
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STEP 4. Check of short to power supply, short to earth, and open circuit
in SSL+, SSL- line in between SRS-ECU connector and side impact sensor (LH) connector.
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Q.
Is the check result normal?
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Go to Step 5.
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Repair the connectors or harness wires.
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STEP 5. Check whether the diagnosis code is reset.
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Q.
Is diagnosis code B1438 or B1439 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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