Short answer: U0110 is a network code: the vehicle ECU has lost communication with the drive motor control module. It is a wiring or module fault, not a battery capacity fault — but a low or unstable 12 V supply can produce it, which is why it is often fixed by a new 12 V battery.
What you see on the dash
Red triangle, “Check Hybrid System”, no READY or an immediate shutdown; other U-codes often appear alongside.
What the code actually means
Controllers talk over a CAN network. When a message from the drive motor controller stops arriving, the vehicle ECU logs U0110 and protects the drivetrain.
Likely causes, in order
- A weak or failing 12 V battery — the classic cause of spurious U-codes.
- Corroded or damaged CAN wiring or connector pins.
- A failed drive motor control module or inverter assembly.
- Water ingress into a connector or module.
How to test before you buy anything
- Check the 12 V battery first — voltage and load test.
- Inspect CAN wiring and connectors between the controllers.
- Check for other U-codes that point at the same bus.
- Only condemn the module after the supply and wiring are proven good.
Repair or replace?
Work backwards from the 12 V supply and the wiring. A U-code on a hybrid almost never means the high-voltage pack needs replacing.
Frequently asked questions
Is U0110 a battery fault?
No. It reports lost communication with the drive motor controller; the high-voltage pack is not the component named.
Can a flat 12 V battery cause U0110?
Yes, and it is one of the most common causes. Load-test the 12 V battery before anything else.
Will clearing U0110 fix it?
It may stay away if the cause was a one-off supply dip. If it returns, the wiring or module needs testing.
Need a pack for this code?
We supply brand-new Ni-MH and Li-ion replacement packs for Toyota, Lexus, Honda and GM hybrids — 144 V to 288 V, with a capacity and resistance report for every unit. Browse packs by vehicle or send us the VIN and the scan and we will confirm fitment before you order.
Codes can have more than one cause. This page is a diagnostic starting point, not a substitute for testing the vehicle.