Code No.B1400 – Driver’s air bag module (squib) system (short -circuited between terminals of the squib circuit) MMC Colt



OPERATION

  • The SRS-ECU judges how severe a collision is by detecting signals from the front air bag analogue G-sensor. If the impact is over a predetermined level, the SRS-ECU sends an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
  • The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

  • DIAGNOSIS CODE SET CONDITIONS

  • This diagnosis code is set if there is abnormal resistance between the input terminals of the driver’s side air bag module (squib). The most likely causes for this code to be set are the followings:
  • Short circuit in driver’s air bag module (squib) or harness
  • Short circuit in the clock spring

  • Improper engaged connector or defective short spring*
  • Short circuit in the clock spring
  • Short circuit between the driver’s air bag module (squib) circuit terminals
  • Damaged connector(s)
  • Malfunction of the SRS-ECU


  • DIAGNOSIS PROCEDURE

    STEP 1. M.U.T.-III CAN bus diagnostics

    Q. Is the CAN bus line found to be normal?

    STEP 2. Check whether the diagnosis code is reset.

    Q. Is the diagnosis code B1400 set?

    STEP 3. Check SRS-ECU connector B-109, clock spring connector B-243 and driver’s air bag module connector B-245 (M.U.T.-III diagnosis code).

    Q. Is diagnosis code B1400 set?

    STEP 4. Check the driver’s air bag module (M.U.T.-III diagnosis code).

    Q. Is diagnosis code B1400 set?

    STEP 5. Check the clock spring (M.U.T.-III diagnosis code).

    Q. Is diagnosis code B1400 set?

    STEP 6. Resistance measurement at the SRS-ECU connector B-109.

    Q. Is the check result normal?

    STEP 7. Check whether the diagnosis code is reset.

    Q. Is diagnosis code B1400 set?

    Author: admin