U0333 code meaning
Software Incompatibility With Gear Shift Control Module B
What U0333 means
With shift-by-wire, both the driver's selector and the unit that actually moves the range are electronic modules; module B denotes a second such unit, either a further selector or the shift actuator. U0333 means its software or calibration does not fit the partner controller. Allison lists it for the sixth-generation controls of its 3000 and 4000 series, released in 2021, as Gear Shift Module 2 Incompatible, next to U0304 for module 1; the same bulletin warns that new push-button selectors do not work with fifth-generation TCMs and that the fitted selector must match the TCM calibration (SIL 14-TR-21). Lexus labels the shift actuator ECU of the 2022 NX 350 and NX 250 with B and reflashed its main and sub calibration in campaign 22LC03. U0291 is lost contact, U0592 invalid data.
U0333 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0333
- Range changes requested at this unit are ignored
- Transmission warning or shift indicator fault
- Vehicle stays in or returns to neutral or park
Common causes of U0333
- Most likelySelector or actuator of another generation or part number fitted
- PossibleTransmission calibration specifies a different selector than the one fitted
- Less likelyShift actuator ECU still on an outdated calibration
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Gear shift module b
What each part of U0333 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 33 | The exact fault in that area. |
What to do next
- Note U0333 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0333
What does U0333 mean?
U0333 means "Software Incompatibility With Gear Shift Control Module B". With shift-by-wire, both the driver's selector and the unit that actually moves the range are electronic modules; module B denotes a second such unit, either a further selector or the shift actuator. It is a generic code, so it means the same on every make.
Is it safe to drive with U0333?
Drive gently and only to a workshop. With U0333 the car can go into limp mode (reduced power) to protect itself.
Will U0333 fail an emissions test?
U0333 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0333 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U0333 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.