B00E4 code meaning
Second Row Right Seat Belt Pretensioner C Deployment Control
What B00E4 means
B00E4 belongs to the outboard seat on the right in the back and its C-stage tensioner. Mercedes-Benz uses it in that sense: every version of LI54.21-P-070658 seen here (December 2019 to June 2020) lists B00E413 as an open in the squib of the tensioning retractor at the rear right. The topic blames higher resistance at the SRS unit connector rather than the tensioner and tells technicians to trace the wire, reseat the plugs and replace the unit only on recurrence. The retractor sits behind the rear trim or in the seat and winds the webbing back when fired, as GM's rescue guide and Joyson explain. No public bulletin from another maker cites B00E4. While the code is stored, the airbag lamp or SRS message stays on.
B00E4 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.3 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of B00E4
- SRS message or airbag lamp permanently displayed
- Right rear passenger loses shoulder-belt tensioning
- Safety note: pyrotechnic tensioner – only work on it with the battery disconnected and after the wait time, ideally at a specialist workshop
Common causes of B00E4
- Most likelyPoor contact at the SRS control unit plug (Mercedes A-Class/CLA/GLB)
- PossiblePlug at the right rear retractor loose after trim removal
- Less likelyAirbag control unit itself faulty (fault returns after reconnecting)
- Less likelySquib in the right rear retractor open
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Second row right pretensioner cSquib circuitSRS control module
What each part of B00E4 means
| B | Body system: airbags, seat belts, power seats, lights and climate control. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| E4 | The exact fault in that area. |
What to do next
- Note B00E4 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about B00E4
What does B00E4 mean?
B00E4 means "Second Row Right Seat Belt Pretensioner C Deployment Control". B00E4 belongs to the outboard seat on the right in the back and its C-stage tensioner. It is a generic code, so it means the same on every make.
Is it safe to drive with B00E4?
B00E4 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B00E4 fail an emissions test?
B00E4 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is B00E4 to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 2.5 hours of work. This is a job for a workshop.
Will B00E4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.