Airbags

B004B — Third Row Right Frontal Airbag Stage 3 Deployment Control Fault

Severity: high Drive with care, to a shop

What B004B means

The SRS (airbag) control module detected a fault in the circuit that controls stage 3 deployment of the third row right frontal airbag. Normally the module continually checks the resistance and integrity of the squib circuits and sends current to them in a crash. With this fault the system may disable that airbag, and in rare cases it may not deploy properly. The exact circuit layout depends on the make and model.

Symptoms

  • Airbag/SRS warning light on the dash
  • Code B004B stored in the SRS module
  • Third row right airbag may be disabled and not deploy in a crash
  • Warning light may flash at key-on
  • Other airbag circuit codes may be stored too

Possible causes

  1. Damaged wiring or a corroded connector in the third row right airbag circuit
  2. Poor connection at the connector under the seat or in the body pillar after interior work
  3. Faulty airbag inflator or squib
  4. Failed SRS control module
  5. Faulty impact or other SRS sensor
  6. Crash damage or wiring disturbed during interior repairs

How to diagnose

  1. Scan with a tool that reads SRS codes and note all codes and whether they are current or history
  2. Ask about recent interior work, seat changes or a collision
  3. Inspect the harness and connectors at the third row right for chafing, corrosion and loose locks
  4. Disconnect the battery and wait as the manufacturer specifies before testing the circuit (airbags can deploy)
  5. Check circuit resistance and shorts to ground or power per the factory wiring diagram, never probing a squib with a standard meter
  6. Check SRS module power supply and ground
  7. Clear the code and see if it returns after key-on and a test drive

Common fixes

  • Repair or replace the damaged harness and connector in the third row right airbag circuit
  • Replace the airbag or inflator if it is the faulty part
  • Replace the SRS module or sensor if confirmed bad, with any coding the brand requires
  • Clear codes and reset the SRS module after repair

Questions and answers

What does code B004B mean?

The SRS module found a fault in the stage 3 control circuit of the third row right frontal airbag. The circuit and the airbag itself need to be diagnosed.

Can I drive with B004B?

The car drives normally, but that airbag, and sometimes the whole system, may not deploy in a crash. Get it checked as soon as you can.

Can I just clear B004B?

You can clear it, but if the cause remains the code will return and the airbag stays in doubt. Find the fault first.

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.