Airbags

B0118 — Passenger Airbag Module Circuit Fault

Severity: high Drive with care, to a shop

What B0118 means

The SRS control unit tests the passenger airbag's squib circuit every time the ignition is turned on. B0118 is set when the measured resistance is out of range, caused by an open circuit, a short to ground or power, or a faulty module. The system can no longer guarantee that the airbag will deploy correctly.

Symptoms

  • SRS or airbag warning light on or flashing
  • Passenger airbag indicator behaving incorrectly
  • Airbag shown as off with an adult in the seat
  • Code returns after being cleared
  • Light may fail the bulb check at startup

Possible causes

  1. Faulty passenger airbag module or its inflator
  2. Damaged or corroded dash wiring harness
  3. Poor contact in the module connector or yellow SRS connector
  4. Conflict with the occupant detection system
  5. Faulty SRS control unit
  6. Connectors not fully seated after dash or seat work

How to diagnose

  1. Scan all modules with an SRS-capable tool and review freeze-frame data and related codes
  2. Ask whether any dash, seat or interior work was done recently
  3. Disconnect the battery and wait the time the manufacturer specifies, then inspect SRS connectors for corrosion, bent pins and loose locks
  4. Inspect the harness behind the dash and glove box for chafing or damage
  5. Check the occupant detection system status and data in the scan tool
  6. Measure circuit resistance per the factory wiring diagram, and never apply power from a test light to an airbag circuit
  7. Substitute a known-good module or a proper simulator per service instructions and see if the fault clears
  8. Clear the code and see if it comes back

Common fixes

  • Repair or replace the damaged section of wiring
  • Clean and secure connectors, replace damaged terminals
  • Replace the passenger airbag module
  • Repair or replace occupant detection components
  • Replace or reprogram the SRS control unit if it is at fault

Questions and answers

Can I unplug an airbag connector myself?

It is risky because an airbag can deploy accidentally. Only work on it with the battery disconnected and after the waiting time the manufacturer specifies. If you lack experience, use a shop.

What does B0118 mean and how serious is it?

It is a fault in the passenger airbag module circuit. It is a serious safety issue because the airbag may not deploy in a crash, so repair it as soon as possible.

Will the code go away if I clear it?

If the cause remains, it will return on the next self-test. Clearing it only makes sense after the repair.

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.