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B0029 — Right Curtain Deployment Control 1

Generic OBD-II · all makesBody

This code indicates the airbag control module has detected an electrical fault in the deployment circuit for the right-side curtain airbag. The module monitors resistance in the squib circuit and sets this code when it finds an open, short to ground, short to voltage, or high resistance that could prevent the airbag from firing during a side-impact or rollover collision.

Symptoms

What causes it — most likely first

1. Faulty right curtain airbag inflator

The squib inside the curtain airbag module can develop an internal open circuit or high resistance due to aging, vibration, or manufacturing defects, causing the control module to detect an out-of-specification resistance.

2. Wiring harness damage

The low-voltage deployment circuit wires running between the airbag control module and the right curtain airbag can break, chafe, or melt due to collision damage or rodent activity, creating an open or short.

3. Corroded or damaged connectors

Moisture intrusion, oxidation, or physical damage at the inline connector near the airbag pillar trim or at the control module can increase resistance or create an open circuit in the deployment loop.

4. Aftermarket equipment interference

Installation of non-factory electrical accessories, remote starters, or alarm systems that tap into the airbag circuit can alter resistance values and trigger deployment control faults.

5. Airbag Control Module failure

While rare, an internal fault within the ACM may cause it to incorrectly report a deployment circuit fault even when the wiring and airbag inflator are within specification.

How it's diagnosed

  1. Visually inspect the wiring harness and connectors for the right curtain airbag, paying special attention to areas where the harness passes through the pillar or roof rail for signs of chafing, corrosion, or disconnection
  2. Disconnect the battery and allow the system to de-energize, then measure the resistance across the curtain airbag squib terminals and compare the reading to manufacturer specification (typically 2.0–3.0 ohms)
  3. Check continuity between the airbag control module connector and the right curtain airbag connector to identify any opens or high-resistance sections in the wiring
  4. Test the deployment circuit for shorts to ground and shorts to battery voltage using a digital multimeter
  5. If the wiring tests satisfactory and resistance is out of spec, replace the right curtain airbag assembly
  6. Only if the airbag and all wiring test normal and no external faults are found, consider testing or replacing the Airbag Control Module

Code facts & related codes

SystemBody
StandardizationSAE generic — identical on every make

Vehicles this code applies to

The definition is universal; the diagnostics are engine-specific. Open your vehicle for the codes documented for it:

2023 Lexus NX450h+2023 Lexus RC F

Frequently asked

Is it safe to drive with the B0029 code active?

The vehicle will operate normally, but the right curtain airbag will likely not deploy in a collision, reducing side-impact protection for occupants. The seatbelt system remains functional, but the airbag warning indicates a compromised supplemental restraint system.

My mechanic says I need to replace the PCM or engine computer to fix this; is that correct?

No. This code relates to the airbag system, not the powertrain. Replacing the Powertrain Control Module (PCM) will not fix B0029. The fault lies in the curtain airbag circuit, wiring, or possibly the Airbag Control Module.

Can I just clear the code with a scanner to turn off the light?

You can clear the code, but the warning light will return immediately if the circuit fault persists. The code will only stay cleared after the underlying electrical problem—such as a broken wire or faulty airbag—is repaired.

Do I need to replace the entire curtain airbag or just a sensor?

The curtain airbag assembly itself contains the deployment squib that this code monitors; there is no separate sensor to replace. If diagnostics confirm the airbag is the cause, the entire curtain airbag module must be replaced.