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DTC B1438 Side impact sensor (Front: LH) communication error
DTC B1439 Side impact sensor (Front: LH) communication impossible
 
 
cautionIf DTC B1438 or B1439 is set in SRS-ECU, be sure to diagnose the CAN bus line.
 
 
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 DTC to the SRS-ECU if a problem occurs.
 
 
DTC SET CONDITIONS
The DTC is set if the communication between the left side impact sensor and SRS-ECU is abnormal (DTC B1438), or impossible (DTC B1439).
 
 
PROBABLE CAUSES
  • Damaged wiring harnesses or connectors
  • Malfunction of the side impact sensor (front: LH)
  • Malfunction of the SRS-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the scan tool ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
 
STEP 2. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Check the DTC.
(1) Erase the diagnostic trouble code.
(2) Ignition: "LOCK" (OFF) position to "ON"
(3) On completion, check that the DTC is not set again.
Is the DTC set?
Go to Step 3.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 3. Check the side impact sensor (front: LH).
(1) Disconnect the negative battery terminal.
(2) Alternate the side impact sensor (front: LH) and the side impact sensor (front: RH), and then install the alternated sensor.
(3) Connect the negative battery terminal.
(4) Erase DTC from memory, and check the diagnostic trouble code.
Is DTC B1438 or B1439 set?
Replace the side impact sensor (front: LH) with a new one (Refer to ).
Go to Step 4.
 
STEP 4. Check of short to power supply, short to ground, and open circuit in SSL+, SSL- line in between SRS-ECU connector and side impact sensor (front: LH) connector.
Is the check result normal?
Go to Step 5.
Repair the connectors or harness wires.
 
STEP 5. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Is DTC B1438 or B1439 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).