[ 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 B1603 DRIVER'S SIDE SEAT BELT PRE-TENSIONER (SQUIB) SYSTEM
Code No.B1603 Seat belt pre-tensioner (driver’s side) (squib) system (short circuit between squib circuit terminals)
 
 
cautionIf the diagnosis code B1603 is set to SRS-ECU, be sure to diagnose the CAN bus line.
 
 
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 seat belt pre-tensioner (squib).
 
 
TROUBLE JUDGEMENT
The code is set when the short circuit occurs between the terminals of SRS-ECU seat belt pre-tensioner (driver’s side) (squib) circuit.
 
 
PROBABLE CAUSES
  • Damaged short spring *
  • Short circuit between terminals of seat belt pre-tensioner (driver’s side) (squib) circuit
  • Damaged connector(s)
  • Malfunction of SRS-ECU
  • Insufficient press of locking button or locking button not pressed
note*: The squib circuit connectors integrate a short spring (which prevents the seat belt pre-tensioner from being unintentionally deployed because of static electricity by shorting the positive wire to the earth wire in the squib circuit when the connectors are disconnected). Therefore, when the above codes are set, the short spring may not be released due to the damaged connector even when the connectors are connected.
 
 
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. B1603 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. Connector check: SRS-ECU, seat belt pre-tensioner (driver’s side).
(1) Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
(2) After disconnecting the SRS-ECU connector, connect it again.
 
(3) After disconnecting the seat belt pre-tensioner (driver's side) harness side connector, connect the connector again. For the seat belt pre-tensioner (driver's side) harness side connector disconnection, use the flat-tipped screwdriver to pull out the harness side connector locking button. After releasing the lock, disconnect the harness side connector.
(4) Connect the negative battery terminal.
(5) After erasing the diagnosis code memory, check the diagnosis code again.
(6) Disconnect the negative battery terminal.
Is the diagnosis code No. B1603 set?
Go to Step 4.
Replace the connector concerned.
 
STEP 4. 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 harness side connector. After releasing the lock, disconnect the seat belt pre-tensioner (driver's side) harness side connector.
 
(3) Connect special tool dummy resistor (MB991865) to special tool resistor harness (MB991884).
(4) Connect special tool resistor harness to the seat belt pre-tensioner (driver's side) 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. B1603 set?
Go to Step 5.
Replace the seat belt with pre-tensioner (driver’s side) (Refer to ).
 
STEP 5. Resistance check 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 SRS-ECU connector short spring in the following operations, disconnect this seat belt pre-tensioner connector, and keep the squib circuit shorted.
Use the flat-tipped screwdriver to pull out the locking button of harness side connector. After releasing the lock, disconnect the seat belt pre-tensioner (driver's side) harness side connector.
 
(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 PTD-, PTD+ line and the short spring, and release the short spring.
(5) Take the measurements below at the SRS-ECU harness side connector.
  • Continuity between PTD-, PTD+ line
OK: No continuity
Is the check result normal?
Go to Step 6.
Repair the wiring harness PTD-, PTD+ line between the SRS-ECU connector and the seat belt pre-tensioner (driver's side) connector.
 
STEP 6. Check whether the diagnosis code is set again.
Is the diagnosis code No. B1603 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 ).