Body, generic

B00E7 Third Row Left Seat Belt Pretensioner C Deployment Control

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B00E7 marks the C-stage tensioner of the third row's left seat, listed after its right-hand twin B00E6. Mercedes-Benz documents it: LI54.21-P-070658 uses B00E713 when the firing pill of the left third-row tensioning retractor shows an open, in the same list as the rear and driver retractors. In that topic the remedy does not start with the tensioner but with fault-tracing the wire and reconnecting the restraint unit plugs; only a recurring fault calls for a new control unit of at least level Q4. Joyson describes this kind of pyrotechnic retractor, which can sit in the body or the seat structure. No other maker publishes B00E7. Airbag lamp on; the left third-row occupant is not tensioned.

Likely causes

Raised resistance at the restraint unit plug
Left third-row retractor connector disturbed during trim or seat work
Control unit below the required level, fault keeps returning
Retractor squib open internally

Symptoms

  • Airbag lamp or fixed SRS message
  • No pretensioning for the left third-row seat
  • Safety note: pyrotechnic device – disconnect the battery and wait before touching it; have it serviced at a specialist workshop

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€50–900
Time0.3–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

third row left pretensioner csquib circuitsrs control module

Related codes

B00E6B00E8B00E0B0076B0056

References: static.nhtsa.gov, static.nhtsa.gov, joysonsafety.com, mbusa.com.