[ Model - ECLIPSE CROSS / Year - 2018 ]
2018 / ECLIPSE CROSS / EC - Workshop Manual
52 -INTERIOR AND SUPPLEMENTAL RESTRAINT SYSTEM(SRS) > 52B-SUPPLEMENTAL RESTRAINT SYSTEM (SRS) > TROUBLESHOOTING > DIAGNOSIS CODE PROCEDURES > DTC B1421 SIDE-AIRBAG SQUIB (RH) OPEN-CIRCUITED
Code No.B1421 Side-airbag module (RH) (squib) system (open circuit of squib circuit)
 
 
cautionIf the diagnosis code B1421 is set to SRS-ECU, be sure to diagnose the CAN bus line.
 
 
OPERATION
In case of side collision, when the impact exceeding the threshold is applied to the vehicle, and when the impact is simultaneously detected (turned ON) by the side impact sensor as well as by the analogue G-sensor in SRS-ECU, the electric current is supplied from SRS-ECU to the side-airbag module (squib) of impacted side.
 
 
TROUBLE JUDGEMENT
The code is set when the open circuit occurs to the SRS-ECU side-airbag module (squib) circuit.
 
 
PROBABLE CAUSES
  • Open circuit to side-airbag module (squib) circuit
  • Poor contact of connector
  • Malfunction of SRS-ECU
 
 
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-IIISE CAN bus diagnostics.
Use M.U.T.-IIISE to diagnose the CAN bus lines.
Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).
 
STEP 2. Check whether the diagnosis code is set again.
(1) Connect the negative battery terminal.
(2) After erasing the diagnosis code memory, check the diagnosis code again.
(3) Disconnect the negative battery terminal.
Is the diagnosis code No. B1421 set?
Go to Step 3.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
 
STEP 3. Diagnosis check by dummy resistor connection.
(1) Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
 
(2) Disconnect the side-airbag module (RH) connector, unlock the connector by sliding the locking button to the direction of the arrow as shown in the figure, and then disconnect the connector.
 
(3) Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991866).
(4)
cautionDo not insert a probe directly into the terminal from the connector front side as the connector contact pressure may be weakened.
Insert the resistor harness probe from the back of side-airbag module (RH) harness side connector.
(5) Connect the negative battery terminal.
(6) After erasing the diagnosis code memory, check the diagnosis code again.
(7) Disconnect the negative battery terminal.
Is the diagnosis code No. B1421 set?
Go to Step 4.
Replace the front seat assembly (Refer to ).
 
STEP 4. Resistance measurement at the SRS-ECU connector and the side-airbag module (RH) connector.
(1) Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
(2) Disconnect the SRS-ECU connector.
 
(3)
dangerTo release the connector short spring in the following operations, disconnect this side-airbag module connector, and keep the squib circuit shorted.
Disconnect the side-airbag module (RH) connector, unlock the connector by sliding the locking button to the direction of the arrow as shown in the figure, and then disconnect the connector.
 
(4)
cautionThe short spring may not be released due to the insufficient insertion, thus insert for 4 mm or more.
Insert a cable tie (width: 3 mm, thickness: 0.5 mm) between the SRS+, SRS- line and the short spring, and then release the short spring.
(5)
cautionDo not insert a test probe directly into the terminal of side-airbag module (RH) harness side connector from the connector front side as the connector contact pressure may be weakened.
Take the measurements below at the SRS-ECU and side-airbag module (RH) harness side connectors.
  • Continuity SRS+ line between SRS-ECU connector and side-airbag module (RH) connector
  • Continuity SRS- line between SRS-ECU connector and side-airbag module (RH) connector
OK: Continuity (less than 2 Ω)
Is the check result normal?
Go to Step 5.
Repair the wiring harness SRS+, SRS- line between the side-airbag module (RH) connector and the SRS-ECU connector.
 
STEP 5. Check whether the diagnosis code is set again.
Is the diagnosis code No. B1421 set?
Replace SRS-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).