B1601 on Lexus: How to Diagnose & Fix
PATS Received Incorrect Key-Code From Transponder
1 Lexus model · 1 documented issue · $400-$1,500 repair
B1601 on Lexus by model: symptoms, diagnosis and fix
The adaptive self-leveling HID headlight system fails due to deterioration of the headlight level sensors mounted at the front and rear suspension. The sensors develop internal failures from exposure to road debris and moisture, causing the headlights to aim incorrectly or trigger warning lights. Replacement sensors are expensive OEM-only parts.
Common Symptoms
- Headlight leveling warning message on dashboard
- Headlights pointing too high or too low
- Headlights not adjusting when vehicle is loaded
- AFS (Adaptive Front-lighting System) warning light
How to Fix
Replace the failed headlight leveling sensor(s). There are typically 3-4 sensors on the LS — two front and one or two rear. Use OEM sensors as aftermarket alternatives have poor fitment. Recalibrate the headlight system with a Lexus diagnostic scan tool after replacement.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- 89405-50070 genuine Lexus front-right height sensorOEM89405-50070
Confirm RWD chassis and VIN against the current catalog before ordering.
- 89406-50100 genuine Lexus front-left height sensorOEM89406-50100
Confirm RWD chassis and VIN against the current catalog before ordering.
- 89405-50100 genuine Lexus front-right height sensorOEM89405-50100 (replaces 89405-50090)
Confirm AWD/hybrid chassis and VIN before ordering.
- 89406-50130 genuine Lexus front-left height sensorOEM89406-50130 (replaces 89406-50120)
Confirm AWD/hybrid chassis and VIN before ordering.
- 89407-50070 genuine Lexus rear-right height sensorOEM89407-50070
Confirm exact LS model, suspension equipment and VIN before ordering.
- 89408-50070 genuine Lexus rear-left height sensorOEM89408-50070
Confirm exact LS model, suspension equipment and VIN before ordering.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Owner tips & cautions
- TipBefore replacing sensors, check the sensor link rods first — they are plastic and break easily. A broken link rod is a $20 fix versus $300+ for a sensor.
B1601 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 B1601 mean on a Lexus?
B1601 stands for "PATS Received Incorrect Key-Code From Transponder." B1601 is a Ford/Lincoln/Mazda body code indicating the Passive Anti-Theft System (PATS) received an incorrect or unrecognized key-code from the ignition key transponder. The anti-theft module could not validate the key, so it may prevent the engine from starting (no-start) and the theft/security light typically flashes. It is not a mechanical engine fault but a security/authentication issue between the key and the immobilizer. Resolving it usually involves key relearning or addressing transponder/wiring faults. On Lexus it is documented across 1 model: LS.
What are the most common causes of B1601?
The most common causes of B1601 are: Unprogrammed, damaged, or wrong transponder key, Key not properly learned to the vehicle, Faulty or weak transponder/key chip, Faulty PATS transceiver ring at the ignition, Damaged wiring/connector between transceiver and module, Faulty PATS/anti-theft control module. The specific cause varies by vehicle.
How much does it cost to fix B1601 on a Lexus?
Published repair estimates on Lexus range from $400 to $1,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for B1601 on a different make?
View B1601 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.