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

cautionIf diagnostic trouble 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 diagnostic trouble code to the SRS-ECU if a problem occurs.
 
 
DTC SET CONDITIONS
This diagnostic trouble 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
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
(1)
cautionTo 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 ."
(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. 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.
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 Use Troubleshooting/Inspection Service Points - 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)
cautionDo 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
Is the measured voltage within the specified range?
Replace the side impact sensor (Front: LH). (Refer to ). Then go to Step 5.
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).
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?
Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1427 sets, replace the SRS-ECU (Refer to ). Then go to Step 5.
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 diagnostic trouble code is reset.
Is diagnostic trouble code B1437 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).