U04B3 code meaning
Invalid Data Received From Planetary Gear Set Control Module
Network system Generic code U04xx codes Check engine light
What U04B3 means
Several hybrid transmissions use planetary gear sets whose shift elements are switched to change the operating mode; two-mode hybrids, for example, combine two extra planetary sets with four clutches to move between electric, power-split and fixed-gear driving. Where a separate module controls such a set and reports its state, U04B3 marks messages from that module that arrive but carry implausible data. No manufacturer documents this code publicly, and SAE gives little more than the name. CARB 1968.2 counts transmission controllers among the emission-critical powertrain units and requires hybrid components to be monitored. U01B2 covers a module that no longer talks. Depending on design, the hybrid system may fall back to a limited mode with a warning light.
U04B3 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U04B3
- Hybrid system or transmission warning
- Reduced power or electric-only driving unavailable
Common causes of U04B3
- PossiblePlanetary gear set control module or its position sensing faulty
- PossibleBus wiring or connector at the transmission damaged or oil-soaked
- Less likelySoftware of module and hybrid controller not matching
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Planetary gear module
What each part of U04B3 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B3 | The exact fault in that area. |
What to do next
- Note U04B3 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 U04B3
What does U04B3 mean?
U04B3 means "Invalid Data Received From Planetary Gear Set Control Module". Several hybrid transmissions use planetary gear sets whose shift elements are switched to change the operating mode; two-mode hybrids, for example, combine two extra planetary sets with four clutches to move between electric, power-split and fixed-gear driving. It is a generic code, so it means the same on every make.
Is it safe to drive with U04B3?
Drive gently and only to a workshop. With U04B3 the car can go into limp mode (reduced power) to protect itself.
Will U04B3 fail an emissions test?
Yes, it can. U04B3 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 U04B3 to fix?
Difficulty: workshop only. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will U04B3 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.