U033B code meaning
Software Incompatibility With Hybrid/EV Battery Interface Control Module B
What U033B means
Module B is the second interface board, and on GM's eAssist mild hybrids it is also the last: bulletin PIT5513D lists exactly two, K112A and K112B, for 2016–2018 Silverado and Sierra and the 2018 LaCrosse, both under the same part number 24282084. Since one spare fits either slot, the part number alone does not tell which position a board serves. FCA's 2017–2018 Pacifica Hybrid shows a related split with maker-specific codes P1A29 and P1A2A for cell supervisory circuits A and B; bulletin 08-047-20 clears them by reflashing the battery pack control module. Neither maker documents U033B itself. U01A1 means B is silent, U04A2 that its data are invalid.
U033B at a glance
- Check engine lightUsually not
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U033B
- Hybrid system or battery warning, often with the check engine lamp on PHEVs
- Electric assist or electric driving reduced
- Fault follows work on the battery pack
Common causes of U033B
- Most likelyBoard B replaced with a spare carrying another software level
- PossibleBattery controller software older than the board it has to accept
- Less likelyIdentical boards A and B swapped during pack repair
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery interface module b
What each part of U033B means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3B | The exact fault in that area. |
What to do next
- Note U033B 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 U033B
What does U033B mean?
U033B means "Software Incompatibility With Hybrid/EV Battery Interface Control Module B". Module B is the second interface board, and on GM's eAssist mild hybrids it is also the last: bulletin PIT5513D lists exactly two, K112A and K112B, for 2016–2018 Silverado and Sierra and the 2018 LaCrosse, both under the same part number 24282084. It is a generic code, so it means the same on every make.
Is it safe to drive with U033B?
Drive gently and only to a workshop. With U033B the car can go into limp mode (reduced power) to protect itself.
Will U033B fail an emissions test?
Yes, it can. U033B is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U033B to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will U033B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.