B0073 code meaning
Second Row Left Seat Belt Pretensioner Deployment Control
What B0073 means
B0073 concerns the pretensioner at the left outer seat of the second row, normally built into the rear retractor. Mitsubishi documents it under exactly this name: with the ignition on, its airbag sensor unit stores B0073 with byte 11, 12, 13, 1A or 1B for a short to ground, a short to power, an open, lines shorted to each other or excessive resistance, and with byte 55 when the stored configuration does not match the vehicle; each fault must last 2 seconds. Toyota's Tundra bulletin T-SB-0057-22 lists B007311 and B007312. IIHS frontal tests with a dummy in the left rear seat show why such units are now spreading to the back row. GM uses the number differently: bulletin 22-NA-170 for the Equinox and Terrain links B0073 to water in the right front seat harness connector X320.
B0073 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of B0073
- Airbag warning lamp on
- Left rear occupant gets no belt pretensioning in a crash
- Safety note: pyrotechnic part in the rear retractor; work only with the system de-energised and preferably at a specialist workshop
Common causes of B0073
- Most likelyPlug at the left rear retractor loose or damaged after trim or seat removal
- PossibleHarness to the left rear pretensioner shorted to ground or power
- Less likelyAirbag module configuration does not match the fitted rear pretensioners (Mitsubishi byte 55)
- Less likelyInternal fault of the left rear pretensioner or of the airbag module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Second row left pretensionerSquib circuitSRS control module
What each part of B0073 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). |
| 73 | The exact fault in that area. |
What to do next
- Note B0073 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 B0073
What does B0073 mean?
B0073 means "Second Row Left Seat Belt Pretensioner Deployment Control". B0073 concerns the pretensioner at the left outer seat of the second row, normally built into the rear retractor. It is a generic code, so it means the same on every make.
Is it safe to drive with B0073?
B0073 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B0073 fail an emissions test?
B0073 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 B0073 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will B0073 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.