B1438

This document has been updated per Mitsubishi TSB# 06-52b-001



DTC B1438: Side Impact Sensor (LH) (Squib) for Power Supply Circuit
DTC B1439: Side Impact Sensor (LH) (Squib) for Communication System

Side Impact Sensor (LH) Circuit:

CIRCUIT OPERATION
The side impact sensor includes an analog G-sensor and CPU, etc. The CPU monitors the analog G-sensor output signal. If the CPU judges that the side-air-bags should be deployed, it sends a fire signal to the SRS-ECU to deploy the side-airbags. Besides that, the CPU diagnoses the internal components of the side impact sensor. If a malfunction occurs, it requests the SRS-ECU to set a diagnostic trouble code.

DTC SET CONDITIONS
These DTC are set if communication between the side impact sensor (LH) and the SRS-ECU is not possible or communication is faulty.

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

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A

STEP 1. Check the side impact sensor (LH) (Using scan tool MB991958, read the diagnostic trouble code).

1. Disconnect the negative battery terminal.
2. Temporarily replace the side impact sensor (LH) with the side impact sensor (RH).
3. Connect the negative battery terminal.
4. Erase the diagnostic trouble code memory, and check the diagnostic trouble code.

Q: Is DTC B1438 or B1439 set?

YES: Replace the side impact sensor (LH) with a new one. Then go to Step 3.

NO: Go to Step 2.










STEP 2. Check the harness wires for open circuit or short circuit between SRS-ECU connector C-29 (terminal No.19 and 20) and side impact sensor (LH) connector D-17 (terminal No.1 and 2).

NOTE: After inspecting intermediate connector C-128 inspect the wiring harness. If the intermediate connector C-128 is damaged, repair or replace it.

Q: Are the harness wires between SRS-ECU connector C-29 (terminal No.19 and 20) and side impact sensor (LH) connector D-17 (terminal No.1 and 2) in good condition?

YES: Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1438 or B1439 sets, replace the SRS-ECU. Then go to Step 3.

NO: Repair the harness wires between SRS-ECU connector C-29 and side impact sensor (LH) connector D-17. Then go to Step 3.

STEP 3. Recheck for diagnostic trouble code.




Check again if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is DTC B1438 or B1439 set?

YES: Return to Step 1.

NO: The procedure is complete.