[ 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 B1412 FRONT PASSENGER'S SIDE AIR BAG SQUIB DRIVE CIRCUIT (EARTH SIDE) SHORT-CIRCUITED
Code No.B1412 Passenger's (front) air bag module (squib) system (shorted to squib circuit earth)
 
 
caution
  • If the diagnosis code B1412 is set to SRS-ECU, be sure to diagnose the CAN bus line.
  • Follow the diagnosis procedure below. If diagnosis code B1412 is set, check squib side circuit.
 
 
OPERATION
Only when the frontal impact exceeding the threshold is simultaneously detected (turned ON) by the front impact sensor as well as by the analogue G-sensor in SRS-ECU, the electric current is supplied from SRS-ECU to the passenger's (front) air bag module (squib).
 
 
TROUBLE JUDGEMENT
The code is set when the SRS-ECU passenger's (front) air bag module (squib) circuit is shorted to earth.
 
 
PROBABLE CAUSES
  • Damaged wiring harness and connectors
  • Passenger's (front) air bag module (squib) harness shorted to earth
  • 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.
Are diagnosis codes No. B1412 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) Use the flat-tipped screwdriver to pull out the locking button of wiring harness side connector, and release the lock.
 
(3) Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991884).
(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 harness side connector ASQ+, ASQ- line.
(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. B1412?
Go to Step 4.
Replace the passenger's (front) air bag module (Refer to ).
 
STEP 4. Resistance measurement at the SRS-ECU 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 harness side connector, and keep the squib circuit shorted.
Use the flat-tipped screwdriver to pull out the locking button of wiring harness side connector, and release the lock.
 
(4)
cautionThe short spring may not be released due to the insufficient insertion. Therefore, insert the insulator for 4 mm or more.
Insert an insulator (width: 3 mm, thickness: 0.5 mm) such as cable tie between the ASQ+, ASQ- line, and then release the short spring.
(5) Take the measurements below at the passenger's (front) air bag module harness side connector.
  • Continuity between ASQ+, ASQ- line and body earth
OK: No continuity
Is the check result normal?
Go to Step 5.
Repair ASQ+, ASQ- line between the SRS-ECU connector and the passenger's (front) air bag module connector.
 
STEP 5. Check whether the diagnosis code is set again.
Is the diagnosis code No. B1412 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 ).