What the source says
The documented condition
Lexus documented two related drivability conditions on some 2016 to 2019 RX 350 and RX 350L vehicles: brief back-and-forth bucking just after the first two upshifts, and a rocking surge below 46 mph while the transmission is in a higher gear with the torque converter fully locked. The bulletin specifies ECM reprogramming after a technician reproduces the exact condition and rules out other faults.
Compare the pattern
Symptoms and vehicle scope
Words owners may use
- Lexus jerks when shifting
- RX 350 bucks at low speed
- car rocks back and forth
- rough first to second shift
- surging under 50 mph
- transmission feels like it is hunting
- hesitation then lurch
Symptoms in the record
- A brief bucking sensation immediately after a 1 to 2 or 2 to 3 upshift
- A repeated rocking or surge not directly tied to a shift
- The surge occurs between 0 and 46 mph with the torque converter in full lock-up
- The sensation dissipates rather than continuing as a constant vibration
Vehicles and limits
- 2016 to 2019 Lexus RX 350
- Specified 2018 to 2019 RX 350L calibrations are included
- Drivetrain, WMI and current calibration determine applicability
Manufacturer position
What the official procedure directs
Lexus directs technicians to reproduce the exact bucking or surge criteria, check for applicable calibration IDs and reprogram the ECM. The bulletin specifically says not to replace the ECM as part of this repair.
Mileage context
The bulletin does not set a mileage threshold. It stated Federal Emissions Warranty coverage of 96 months or 80,000 miles for the specified condition, subject to the vehicle's in-service date and eligibility.
Original evidence
Open the documents behind this record.
Manufacturer bulletin · L-SB-0032-19 Rev1 · Sep 26, 2019
Vehicle bucking on 1 to 2 or 2 to 3 upshifts and surge between 0 to 46 mph
The bulletin defines the two drivability conditions and the applicable ECM reprogramming procedure.
Repair paths and safe checks
Match the action to the evidence.
Confirm the drive pattern and update the ECM calibration
A Lexus technician uses vehicle data to reproduce the published condition, checks the current calibration and installs the applicable updated ECM software.
Do not replace transmission parts solely from the symptom wording. The bulletin applies only when its operating criteria and calibration checks match.
Record when the motion occurs
From the passenger seat or after the trip, note the road speed and whether the event follows a shift. Add the engine temperature and any warning light.
Do not attempt repeated acceleration tests in traffic or operate a phone while driving.
Record reviewed in the source on August 2, 2026. Confirm the current document and VIN instructions before arranging work.
How we check a problem · All records for the 2019 Lexus RX 350