Airbags

B0078 — Third Row Right Seatbelt Pretensioner Circuit Fault

Severity: high Drive with care, to a shop

What B0078 means

The SRS control module continuously tests the squib circuit of the third row right seatbelt pretensioner for correct resistance, opens and shorts. B0078 is set when that circuit falls outside the expected range. The module may then disable that pretensioner, so it may not fire in a crash.

Symptoms

  • SRS / airbag warning light on the dash
  • B0078 stored in the SRS module
  • Third row right pretensioner may not fire in a crash
  • Light may stay on or flash after startup

Possible causes

  1. Damaged, loose or corroded connector at the pretensioner
  2. Broken, chafed or shorted wiring, often under trim or near folding seats
  3. Faulty third row right seatbelt pretensioner
  4. SRS control module fault
  5. Connector left unplugged or damaged after seat or trim work

How to diagnose

  1. Scan with a tool that reads SRS codes and confirm B0078 and whether it is current or history
  2. Note any other SRS circuit codes, clear the code and see if it returns
  3. Inspect the connector and harness at the pretensioner and under the cargo trim for water, corrosion or pinching
  4. Check whether seats or trim were removed recently and that all connectors are fully seated
  5. Disconnect the battery and wait as the manufacturer specifies, then test circuit resistance per service data; never probe a squib with a standard test light
  6. Test the circuit for opens, shorts to ground and shorts to power
  7. If wiring is good, replace the pretensioner and retest; then suspect the SRS module

Common fixes

  • Repair the wiring or replace the damaged connector in the pretensioner circuit
  • Replace the third row right seatbelt pretensioner
  • Replace or reprogram the SRS module if confirmed faulty
  • Clean and secure connectors, then clear the code and verify

Questions and answers

What does B0078 mean?

It signals a fault in the control circuit of the third row right seatbelt pretensioner. The SRS module sees abnormal readings and may disable that safety device.

Can I fix an SRS circuit myself?

Visual checks of connectors are fine, but work on pretensioners and airbags must be done with the battery disconnected and per service procedures. If unsure, see a shop.

Is it safe to drive with the SRS light on?

The car will run, but the restraint system may not work fully in a crash. Get it repaired as soon as possible.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.