EN

Severity: Critical Code type: Generic (all makes)

U0110 Code: Lost Communication With Drive Motor Control Module A

The hybrid/EV system lost contact with the module that runs electric drive motor A.

Safety first · Consult a professional

  • High-voltage system: hybrid/EV battery circuits (orange cables) can be lethal. Do not open or probe them — leave this to a trained EV technician.

At a glance

Severity: 5/5 – Critical5/5

Severity: Critical

Meaning
Lost Communication With Drive Motor Control Module A
System
Module Communication · Network
Safe to drive?
No — stop driving
Typical repair cost
$50–$5,500
DIY difficulty
Hard

In hybrids and EVs, drive motor control module A is the electronics that commands the inverter feeding the main traction motor, usually built into the inverter assembly under the hood of a hybrid or on the drive unit of an EV. The hybrid or vehicle control module logs U0110 when that module's messages stop. Because it can no longer control propulsion torque safely, the system typically opens the high-voltage contactors or refuses to enter READY, so the car either won't go or coasts with a 'check hybrid system' style warning. The first suspect is surprisingly ordinary: a weak 12-volt auxiliary battery, which powers all of the control electronics even though the car has a huge high-voltage pack.

How to read U0110

How to read U0110U10213104
  1. U Network
  2. 0 Generic (SAE)
  3. 1 Module Communication
  4. 10 Specific fault

Symptoms

  • Car won't enter READY; dash shows a hybrid or EV system warning
  • Loss of drive power while moving, often with a chime and red warning
  • Engine runs on a hybrid but the car won't move, or power is severely limited
  • Multiple warning lights: check engine, hybrid system, brake, traction
  • Scan tool can't reach the motor control or inverter module

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Weak or failing 12 V auxiliary battery, or corroded terminals on it 30%
  2. Blown fuse or failed relay for the motor control module's low-voltage supply 16%
  3. Inverter cooling problem (failed inverter coolant pump, low coolant) causing the module to shut down 16%
  4. Internal failure of the motor control module or inverter assembly 16%
  5. Loose or corroded low-voltage connector at the inverter 14%
  6. Damaged CAN wiring to the inverter, e.g. after front-end collision repair 8%

Diagnosis step by step

Diagnostic flow: U01101Test the 12 V auxiliary batteryfirst2Scan every module and notefreeze-frame3Check low-voltage fuses and relays4Inspect inverter coolant and pump5Leave high-voltage work to trainedtechs

  1. Test the 12 V auxiliary battery first

    Measure the 12 V battery at rest; below about 12.2 V it is discharged, and a load test tells you whether it can still hold up the control electronics. Clean the terminals and check the main ground. Many hybrid no-READY complaints disappear with a healthy 12 V battery.

    Tools: Multimeter

  2. Scan every module and note freeze-frame

    Use a scan tool with hybrid/EV coverage. Record which modules respond and any temperature, voltage or interlock codes stored with U0110; they show whether the module shut itself down or simply lost power.

    Tools: OBD-II scanner

  3. Check low-voltage fuses and relays

    Using the wiring diagram, test the fuses and relays that feed the motor control module and the inverter's control side with a meter. This is 12 V work only; the high-voltage system stays untouched.

    Tools: Multimeter

  4. Inspect inverter coolant and pump

    Check the separate inverter coolant reservoir level and, with the system in READY if possible, confirm the inverter pump runs. An overheating inverter can drop off the network to protect itself.

    Tools: Flashlight

  5. Leave high-voltage work to trained techs

    Checks at the inverter's low-voltage connector, CAN wiring and the inverter itself require the high-voltage system to be de-energized by a technician trained for that work, using insulated tools and the manufacturer's disable procedure. Replacement inverters usually need programming.

    Tools: Gloves

Where the parts are

Charging system and control modules – U01101234567
Charging system and control modules
  1. 1Battery
  2. 2Alternator
  3. 3Engine computer (ECM)
  4. 4CAN bus
  5. 5Transmission
  6. 6Wheel speed sensor
  7. 7High-voltage battery

Repair options & costs

RepairDIY?Estimated cost
Replace 12 V auxiliary battery Yes $180–$400
Replace fuse/relay, clean low-voltage connector No $50–$250
Replace inverter coolant pump and bleed system No $250–$700
Replace inverter / motor control module assembly with programming No $2,000–$5,500

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Emissions / smog test impact

Will fail

U0110 sets the check engine or hybrid warning light on hybrids, which fails a US emissions test; many states exempt full EVs from emissions testing, but the fault still needs fixing to drive the car.

Frequently asked questions

Why would a small 12 V battery stop a hybrid from moving?

All the computers, including the motor control module and the relays that connect the high-voltage battery, run on 12 V. If that battery sags, the modules drop off the network and the high-voltage system won't switch on.

Can I jump-start my hybrid with U0110?

You can jump the 12 V system at the terminals the owner's manual shows, which often brings it back to READY if the battery was the problem. Never connect anything to high-voltage parts.

Is U0110 a sign the high-voltage battery is failing?

Not directly. It's about communication with the motor control electronics. A failing high-voltage battery usually sets its own codes, such as a battery pack deterioration code.

Can any shop fix this?

Low-voltage checks, yes. Anything involving the inverter or orange cables needs a technician trained and equipped for high-voltage work.

Sources