B1650: How to Diagnose & Fix — Occupant Classification System / Paint Code Configuration (manufacturer-specific)
3 vehicles · 2 makes · $250-$2,500 repair
How to diagnose and fix B1650: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Lexus NX · 2023–2024
An electrical connection inside the steering column's spiral cable assembly — the coiled ribbon that carries signals to the rotating steering wheel — may be insufficiently welded. The connection can separate in service, which deactivates the driver's frontal airbag and puts the vehicle out of compliance with FMVSS 208, Occupant Crash Protection. Critically, campaign 25V040000 targets vehicles that may have been incorrectly repaired under the earlier recall 23V-480, so a car whose records show that prior repair is not necessarily safe. Owner letters were mailed March 17, 2025; the Lexus campaign number is 25LA02.
Common Symptoms
- SRS or airbag warning light illuminated
- Horn does not work
- Steering wheel audio or cruise controls stop responding
- Warning light appears after steering wheel work or a prior recall repair
How to Fix
Do not assume the earlier 23V-480 repair covered this — the entire point of campaign 25V040000 is that some of those repairs were performed incorrectly. Check the VIN with Lexus or NHTSA and have the dealer inspect and replace the spiral cable assembly as necessary, free of charge. Unlike many latent airbag defects, this one usually announces itself: a separated spiral cable typically lights the SRS warning and often disables the horn and the steering wheel controls at the same time, since they share the same ribbon. Treat that combination of symptoms as this recall until proven otherwise, and do not let an independent shop clear the code without replacing the assembly.
Sources for this issue (1)
Lexus LX · 2022–2024
Multiple 2022-2024 Lexus LX owners reported persistent SRS/airbag warning messages and dealer diagnoses related to the front passenger occupant classification system and related airbag components. This generation shares Toyota/Lexus safety-system campaigns affecting front seat occupant sensing and airbag readiness, and owners describe warning lights, repeated dealer visits, and concerns about whether the passenger airbag will deploy correctly. Because the issue directly affects restraint-system operation, it is considered high severity even when the repair itself is covered by recall or warranty.
Common Symptoms
- SRS warning light illuminated
- Airbag system malfunction message
- Passenger airbag OFF/ON status behaving abnormally
- Warning appears after moving front passenger seat
- Repeated dealer visits for airbag-related faults
How to Fix
Scan the SRS system with a Toyota/Lexus-capable diagnostic tool and inspect the passenger seat weight/occupant classification components, seat harnesses, and any applicable recall campaign status by VIN. Dealers typically perform recall remedies, recalibration, or replacement of affected seat sensor/airbag-related parts, then clear codes and verify the occupant detection status with a seat calibration procedure. If the warning returns, wiring under the seat and connector tension should be checked carefully.
Hyundai Accent · 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.
Common Symptoms
- SRS/airbag warning light stays on
- PASSENGER AIRBAG OFF light stays lit with an adult in the seat
- Airbag light comes on only when someone sits in the passenger seat
- Intermittent light that changes with seat load
How to Fix
Pull the SRS codes with a scanner that reads airbag modules (a generic OBD-II reader will not show them). First inspect the connectors under the passenger seat for corrosion, a partially seated plug, or a chafed harness from the seat rails - loose connections cause the same fault and cost nothing. If the mat itself is bad, the OEM route is a passenger seat cushion assembly replacement plus an OCS calibration/zeroing procedure at the dealer. Far cheaper alternatives owners use: an aftermarket replacement sensor mat/bypass emulator, or sending the seat cushion out to a sensor rebuild service. After any repair the OCS system must be recalibrated or the light returns.
Sources for this issue (3)
Find B1650 by make
Browse every documented model and issue for your make.
B1650 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does B1650 mean?
B1650 stands for "Occupant Classification System / Paint Code Configuration (manufacturer-specific)." B1650 is a manufacturer-specific body code whose exact meaning depends on the vehicle maker. On several vehicles it is reported as an Occupant Classification System (OCS) malfunction, the system that senses the front passenger's weight/presence to decide whether and how forcefully to deploy that airbag; on some Ford-family vehicles a B1650-range code instead refers to a paint/option configuration value. Because the definition differs by brand, confirm against the specific make. If it is OCS-related, treat it as airbag-related and have it diagnosed promptly.
What are the most common causes of B1650?
The most common causes of B1650 are: Faulty occupant classification (passenger seat weight) sensor or mat, Damaged wiring or connector to the seat occupant sensor, OCS module needs recalibration after a seat or sensor change, Faulty occupant classification control module, Incorrect option/paint configuration data in the module (on makes using that definition), Faulty body control or restraints control module. The specific cause varies by vehicle.
How much does it cost to fix B1650?
Repair costs for B1650 range from $250 to $2,500, depending on the vehicle and root cause.
Which vehicles are affected by B1650?
Au7o has documented B1650 across 3 vehicle models from 2 manufacturers: Hyundai, Lexus.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.