B1438

DTC B1438 Side Impact Sensor (Front: LH) Communication Error
DTC B1439 Side Impact Sensor (Front: LH) Communication Impossible













CAUTION:
If the diagnosis code B1438 or B1439 is set to SRS-ECU, be sure to diagnose the CAN bus line.

CIRCUIT 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.

DTC SET CONDITIONS

The diagnosis code is set if the communication between the side impact sensor (Front: LH) and SRS-ECU is abnormal (No. B1438), or impossible (No. B1439).

TROUBLESHOOTING HINTS

- Damaged wiring harnesses or connectors
- Malfunction of the side impact sensor (Front: LH)
- Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics

Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

YES Go to Step 2
NO Repair the CAN bus line CAN Bus Diagnostics Chart).
STEP 2. Check whether the diagnosis code is reset.

Check again if the diagnosis code is set.

(1)Erase the diagnosis code.

(2)Ignition: "LOCK" (OFF) position to "ON"

(3)On completion, check that the diagnosis code is not reset.

Q. Is the diagnosis code set?

YES Go to Step 3
NO There is an intermittent malfunction such as poor engaged connector(s) or open circuit How to Cope With Intermittent Malfunctions).
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 diagnosis code from memory, and check the diagnosis code.

Q. Is diagnosis code B1428 or B1429 set?

YES Replace the side impact sensor (Front: LH) with a new one (Refer to Removal and Installation).
Go to Step 5.
NO Go to Step 4
STEP 4. Check the harness wires for open circuit and short circuit between SRS-ECU connector C-125 (terminal No.41 and 42) and side impact sensor (Front: LH) connector D-29 (terminal No.1 and 2).

Q. Are the harness wires between SRS-ECU connector C-125 (terminal No.41 and 42) and side impact sensor (Front: LH) connector D-29 (terminal No.1 and 2) in good condition?

YES Go to Step 5
NO Repair the harness wires between SRS-ECU connector C-125 (terminal No.41 and 42) and side impact sensor (Front: LH) connector D-29 (terminal No.1 and 2).
STEP 5. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1438 or B1439 set?

YES Replace the SRS-ECU (Refer to Service and Repair).
NO An intermittent malfunction is suspected How to Cope With Intermittent Malfunctions).