Airbags

B0077 — Airbag/SRS Sensor Circuit Malfunction

Severity: high Drive with care, to a shop

What B0077 means

The SRS control module constantly monitors its impact sensors and the pretensioner circuits, checking resistance and signal values. B0077 is stored when one of these circuits is out of range, such as an open, a short, a poor connection or a missing signal. The exact circuit depends on the make and model, so confirm it in the vehicle's wiring information.

Symptoms

  • SRS/airbag warning light on or flashing
  • Related airbag or pretensioner may be disabled
  • B0077 stored in the SRS module and visible on a scan
  • Passenger airbag status light may act oddly if the circuit is related

Possible causes

  1. Faulty impact sensor or seatbelt pretensioner
  2. Open, shorted or corroded wiring and connectors in the SRS circuit
  3. Wiring damaged under a seat from seat movement or past repairs
  4. Loose or corroded connector after interior work
  5. Faulty SRS control module or communication problem

How to diagnose

  1. Scan all modules with an SRS-capable tool and record every code before clearing anything
  2. Identify which sensor or circuit B0077 refers to in the manufacturer's information
  3. Inspect connectors and harness in that area for corrosion, chafing or unlatched plugs
  4. Ask about recent repairs, seat removal, interior or body work
  5. With the battery disconnected and the required wait time observed, check circuit resistance and shorts to ground or power
  6. Never probe airbag squib circuits with an ordinary meter; use only methods approved by the manufacturer
  7. Clear the code after repair and confirm it does not return

Common fixes

  • Repair or replace damaged wiring and connectors
  • Replace the faulty impact sensor or pretensioner
  • Replace or reprogram the SRS control module if it is confirmed faulty
  • Clean terminals and secure connectors properly

Questions and answers

What does B0077 mean?

It indicates a fault in an airbag/SRS sensor circuit. The module saw an abnormal signal or resistance and logged the code. Which sensor is involved depends on the vehicle.

Is it safe to drive with the SRS light on?

You can drive, but airbags or pretensioners may not work in a crash. Get it checked soon.

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.