Airbags

B0018 — Passenger Frontal Airbag Deployment Loop Voltage Out of Range / Short

Severity: high Drive with care, to a shop

What B0018 means

The SRS control module continuously monitors the voltage and resistance of the passenger frontal airbag deployment loop (the squib circuit). B0018 means that voltage is outside the allowed range or a short to ground or to voltage was detected. In that state the system cannot guarantee deployment and usually disables the airbag.

Symptoms

  • Airbag (SRS) warning light is on
  • Passenger airbag may not deploy in a crash
  • Other SRS components, such as pretensioners, may be disabled
  • Passenger airbag off indicator may behave abnormally

Possible causes

  1. Short to ground or to voltage in the passenger airbag loop wiring
  2. Damaged or corroded wiring or connector in the SRS circuit
  3. Faulty passenger airbag module in the instrument panel
  4. Faulty SRS control module (SDM)
  5. Connector or wiring disturbed by earlier dash work or moisture

How to diagnose

  1. Scan the SRS system with a capable tool and note all codes, including related ones
  2. Disconnect the battery and wait the time specified by the manufacturer to avoid accidental deployment
  3. Inspect connectors under the dash and at the SRS module for corrosion, bent pins and moisture
  4. Inspect the harness for chafing, pinching and signs of previous interior repairs
  5. Check the loop for shorts to ground and voltage per the factory wiring diagram, never applying power or using a standard ohmmeter on the squib
  6. Review scan tool data for the circuit and compare it with specifications
  7. Clear the code and see whether it returns

Common fixes

  • Repair or replace damaged wiring and connectors in the passenger airbag loop
  • Replace the passenger airbag module if it is faulty
  • Replace or reprogram the SRS control module
  • Clean the contacts and remove the source of moisture

Questions and answers

Can I test an airbag circuit myself?

It is risky because the squib can fire from stray current. Disconnect the battery, observe the wait time, and never apply voltage or use a regular ohmmeter on the squib. If you lack experience, see a shop.

Will B0018 go away on its own?

A momentary poor connection may turn the light off, but the fault usually remains and the code returns. The airbag may be disabled meanwhile, so have it checked promptly.

Will the passenger airbag deploy with the SRS light on?

Most likely not. With a circuit fault the module normally disables the airbag, so you should not count on it in a crash.

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.