B1437

DTC B1437: Side Impact Sensor (Front: LH) Voltage Error













CAUTION:
If diagnosis code B1437 is set in the SRS-ECU, always diagnose the CAN main 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

This diagnosis code will set when the power supply voltage to the side impact sensor (Front: LH) remains less than a predetermined value for one second.

TROUBLESHOOTING HINTS

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

DIAGNOSIS PROCEDURE

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

Connect scan tool MB991958. Refer to "How to connect the scan tool Reading and Clearing Diagnostic Trouble Codes."

(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.

Q. Is the CAN bus line found to be normal?

YES Go to Step 2.
NO Repair the CAN bus line CAN Bus Diagnostics Chart).
STEP 2. 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 the DTC 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) power supply circuit.
Measure the voltage at the side impact sensor (Front: LH) connector D-29.

(1)Disconnect the negative battery terminal.

(2)Disconnect side impact sensor (Front: LH) connector D-29, and measure at the wiring harness side.

(3)Connect the negative battery terminal.

(4)Turn the ignition switch to the "ON" position.





(5)
CAUTION:
Do not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.

Measure the voltage between D-29 harness side connector terminal 1and ground.
Voltage should measure 9 volts or more

Q. Is the measured voltage within the specified range?

YES Replace the side impact sensor (Front: LH). (Refer to Removal and Installation).
Then go to Step 5.

NO Go to Step 4.

STEP 4. Check the harness wires for open circuit or short circuit between SRS-ECU connector C-125 (terminal No.41) and side impact sensor (Front: LH) connector D-29 (terminal No.1).

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

YES Erase the diagnostic trouble code memory, and check the diagnostic trouble code.
If DTC B1427 sets, replace the SRS-ECU (Refer to Service and Repair). Then go to Step 5.
NO Repair the harness wires between SRS-ECU connector C-125 and side impact sensor
(Front: LH) connector D-29. Then go to Step 5.
STEP 5. Check whether the diagnosis code is reset.

Q. Is diagnosis code B1437 set?

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