Code No.B1438: Side impact sensor (LH) communication error
Code
No.B1439: Side impact sensor (LH) communication impossible
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If diagnosis code B1438 or B1439 is set in the
SRS-ECU, always diagnose the CAN main 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
These diagnosis codes are set if
communication between the side impact sensor (front) (LH) and the SRS-ECU is
not possible or faulty.
PROBABLE CAUSES
- Damaged wiring harnesses or connectors
- Malfunction of the side impact sensor (front) (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 54D, 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 (front) (LH).
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(1)Disconnect the negative battery terminal.
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(2)Replace the side impact sensor (front) (LH) with the side
impact sensor (front) (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 B1428 or B1429 set?
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Replace the side impact sensor
(front) (LH) with a new one (Refer to ). Go to Step 4.
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Repair the harness wires between
SRS-ECU connector D-25 (terminal No.19 and 20) and side impact sensor
(front) (LH) connector E-18 (terminal No.2 and 1). Than go to Step 4
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STEP 4. 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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The
procedure is complete.
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