B1427
DTC B1427: Side Impact Sensor (RH) Power Supply Circuit SystemSide Impact Sensor (RH) Circuit:
CAUTION: If DTC B1427 is set in the SRS-ECU, always diagnose the CAN main bus line.
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-airbags should be deployed, it sends a fire signal to the SRS-ECU to deploy the side-airbags. In addition, 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
This DTC will set when the power supply voltage to the side impact sensor (RH) remains less than a predetermined value for five seconds. However, if the system returns to normal condition, code number B1427 will be erased automatically and the SRS warning light will go out.
TROUBLESHOOTING HINTS
- Damaged wiring harness or connectors
- Malfunction of the side air bag module (RH) (squib)
- Malfunction of the SRS-ECU
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A (Vehicles with CAN communication system)
- MB991223 (MB991222): Harness set (Probe)
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
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.
1. Connect scan tool MB991958. Refer to "How to connect the scan tool." Reading 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 (Refer to Diagnosis). Diagnostic Trouble Code Descriptions
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 (Refer to How to Cope with Intermittent Malfunction).
STEP 3. Check the side impact sensor (RH) power supply circuit. Measure the voltage at the side impact sensor (RH) connector D-35.
1. Disconnect the negative battery terminal.
2. Disconnect side impact sensor (RH) connector D-35, and measure at the wiring harness side.
3. Connect the negative battery terminal.
4. Turn the ignition switch to the "ON" position.
CAUTION: Do not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
5. Measure the voltage between D-35 harness side connector terminal 2 and ground.
Voltage should measure 9 volts or more
Q: Is the measured voltage within the specified range?
YES: Replace the side impact sensor (RH). 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-120 (terminal No.63 and 64) and side impact sensor (RH) connector D-35 (terminal No.1 and 2).
Q: Are the harness wires between SRS-ECU connector C-120 (terminal No.63 and 64) and side impact sensor (RH) connector D-35 (terminal No.1 and 2) in good condition?
YES: Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1427 sets, replace the SRS-ECU. Then go to Step 5.
NO: Replace the harness wires between SRS-ECU connector C-120 and side impact sensor (RH) connector D-35. Then go to Step 5.
STEP 5. 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 B1427 set?
YES: Return to Step 1.
NO: The procedure is complete.