B1620 on Hyundai
Airbag System Control Module (SRSCM) Internal Fault
B1620 on Hyundai vehicles indicates airbag system control module (srscm) internal fault. Au7o has documented this code across 1 Hyundai model — most commonly on Accent. The Airbag Control Unit runs a self-diagnostic routine for roughly six seconds after the ignition is turned on. B1620 sets when that self-test reports an internal failure of the module itself. Hyundai has issued two separate remedies over time: Service Campaign TX8 reprograms the ACU because sufficient vibration during the diagnostic window (for example a door being slammed) could cause the module to erroneously detect an internal fault; Warranty Extension TXXQ / TSB 24-BE-014H lists B1620 as a genuine internal-failure code requiring ACU replacement on Accent (HC). Typical repair costs on Hyundai range from $250 to $2,400, depending on the specific model and root cause.
Common Causes of B1620
- •Genuine internal electronic failure of the ACU/SRSCM (remedy: ACU replacement per Warranty Extension TXXQ)
- •Outdated B1620 diagnostic logic — vibration such as a slammed door during the post-ignition self-test falsely sets the code (remedy: ACU reprogramming per Service Campaign TX8)
- •Water intrusion at the module location shorting the board
- •Low or unstable supply voltage to the ACU during the self-test
B1620 on Hyundai by Model
Hyundai Accent(1 issue)
- Passenger Occupant Classification Seat Sensor Mat Failure (Airbag / PASSENGER AIRBAG OFF Light)2006-2017
The occupant classification sensor mat built into the front passenger seat cushion fails internally - the printed pressure-sensing traces crack with repeated loading. The car then either lights the SRS/airbag warning lamp with an OCS fault stored, or leaves the PASSENGER AIRBAG OFF indicator lit with an adult sitting in the seat, meaning the passenger airbag will not deploy in a crash. It affects MC (2006-2011) Accents heavily and continues on later cars, and it is well documented across Hyundai/Kia models generally. The financial sting is that Hyundai does not sell the mat separately - the fix is the entire lower seat cushion assembly, and forum owners have posted dealer quotes in the $1,200-$2,400 range for what is a failed sensor pad.
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View B1620 across all makes →Frequently Asked Questions
What does B1620 mean on Hyundai?▼
B1620 stands for "Airbag System Control Module (SRSCM) Internal Fault." The Airbag Control Unit runs a self-diagnostic routine for roughly six seconds after the ignition is turned on. B1620 sets when that self-test reports an internal failure of the module itself. Hyundai has issued two separate remedies over time: Service Campaign TX8 reprograms the ACU because sufficient vibration during the diagnostic window (for example a door being slammed) could cause the module to erroneously detect an internal fault; Warranty Extension TXXQ / TSB 24-BE-014H lists B1620 as a genuine internal-failure code requiring ACU replacement on Accent (HC). On Hyundai specifically, this code is documented across 1 model.
What causes B1620 on Hyundai vehicles?▼
Common causes on Hyundai: Genuine internal electronic failure of the ACU/SRSCM (remedy: ACU replacement per Warranty Extension TXXQ), Outdated B1620 diagnostic logic — vibration such as a slammed door during the post-ignition self-test falsely sets the code (remedy: ACU reprogramming per Service Campaign TX8), Water intrusion at the module location shorting the board, Low or unstable supply voltage to the ACU during the self-test. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix B1620 on a Hyundai?▼
Repair costs on Hyundai range from $250 to $2,400, depending on the specific model and root cause.
Which Hyundai models have B1620 documented?▼
Au7o has documented B1620 on 1 Hyundai model: Accent.