[ 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 B1634 DRIVER'S KNEE AIR BAG SQUIB CIRCUIT (POWER SUPPLY)
Code No.B1634 Knee air bag module (squib) system (shorted to squib circuit power supply)
 
 
cautionIf the diagnosis code B1634 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 knee air bag module (squib).
 
 
TROUBLE JUDGEMENT
The code is set when the SRS-ECU driver's knee air bag module (squib) circuit is shorted to power supply.
 
 
PROBABLE CAUSES
  • Poor contact of connector
  • Driver's knee air bag module (squib) harness shorted to power supply
  • 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. B1634 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 harness side connector. After releasing the lock, disconnect the knee air bag module harness side connector.
 
(3) Connect dummy resistor (MB991865) to special tool resistor harness (MB991884).
(4) Connect the special tool resistor harness to the knee air bag module 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. B1634 set?
Go to Step 4.
Replace the knee air bag module (Refer to ).
 
STEP 4. Voltage 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 SRS-ECU 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 harness side connector. After releasing the lock, disconnect the knee air bag module 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 KDS-, KDS+ line and the short spring, and release the short spring.
(5) Connect the negative battery terminal.
(6) Ignition switch: ON
(7) Take the measurements below at the SRS-ECU harness side connector.
  • Voltage between KDS-, KDS+ line and body earth
OK: 1 V or less
(8) Disconnect the negative battery terminal.
Is the check result normal?
Go to Step 5.
Repair the wiring harness KDS-, KDS+ line between the SRS-ECU connector and the knee air bag module connector.
 
STEP 5. Check whether the diagnosis code is set again.
Is the diagnosis code No. B1634 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 ).