Code No.B1438:
Side Impact Sensor (LH) (Squib) for Power Supply Circuit
Code No.B1439:
Side Impact
Sensor (LH) (Squib) for Communication System
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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 includes an analogue G sensor and
CPU, etc. The CPU monitors the analogue
G sensor output signal. If the CPU judges that the side-airbags and curtain
air bags should
be deployed, it sends a fire signal to the SRS-ECU to deploy the side-airbags
and curtain air
bags. In addition, the CPU diagnoses the internal components of the side
impact sensor. If a malfunction
occurs, it requests the SRS-ECU to set a diagnosis code.
DIAGNOSIS CODE SET CONDITIONS
These diagnosis codes are set if
communication between the side impact sensor (LH) and
the SRS-ECU is not possible or faulty.
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 54F, 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) (M.U.T.-III diagnosis
code).
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(1)Disconnect the negative battery terminal.
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(2)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 B1428 or B1429 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 the harness wires for open circuit or short circuit
between SRS-ECU connector C-120 (terminal No.19 and 20) and side impact
sensor (LH) connector
D-18 (terminal No.1 and 2).
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Q.
Are the harness wires between SRS-ECU connector C-120 (terminal No.19 and
20) and
side impact sensor (LH) connector D-18 (terminal No.1 and 2) in good
condition?
Go to Step 5 .
Repair the harness wires between
SRS-ECU connector C-120 (terminal No.19 and 20)
and side impact sensor (LH) connector D-18 (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 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 Use
Troubleshooting/Inspection Service
Points ).
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