U0119 code meaning
Lost Communication With Fuel Cell Control Module
What U0119 means
U0119 is the slot for losing the fuel cell control module, the controller that runs the hydrogen stack of a fuel cell vehicle: air compressor, hydrogen supply, humidity, stack cooling and the electrical output handed to the drive. Older code tables still label U0116–U0120 as reserved, so some scan tools show no text for it. No manufacturer documents the code publicly; Toyota, Hyundai and Honda have sold series fuel cell cars, yet their service data are not open. As a general frame, CARB asks for a dedicated code whenever a digital partner falls silent. U0468 covers invalid data from the same module, U0293 the hybrid/vehicle system controller. Once the link drops, the vehicle controller cannot request stack power: expect a system warning, operation only from the buffer battery or no READY.
U0119 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0119
- Fuel cell or drive system warning
- Power limited to the buffer battery
- Vehicle does not reach READY
Common causes of U0119
- Most likelyFuel cell controller without 12 V supply or ground
- PossibleDamaged CAN wiring or connector between stack controller and vehicle controller
- PossibleSoftware fault or missing update in one of the controllers
- Less likelyFuel cell control module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel cell moduleCAN bus wiring
What each part of U0119 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 19 | The exact fault in that area. |
What to do next
- Note U0119 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 U0119
What does U0119 mean?
U0119 means "Lost Communication With Fuel Cell Control Module". U0119 is the slot for losing the fuel cell control module, the controller that runs the hydrogen stack of a fuel cell vehicle: air compressor, hydrogen supply, humidity, stack cooling and the electrical output handed to the drive. It is a generic code, so it means the same on every make.
Is it safe to drive with U0119?
Drive gently and only to a workshop. With U0119 the car can go into limp mode (reduced power) to protect itself.
Will U0119 fail an emissions test?
U0119 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 U0119 to fix?
Difficulty: workshop only. A typical repair takes 1 to 6 hours of work. This is a job for a workshop.
Will U0119 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.