Lost Communication With Drive Motor Control Module "A"

What it means

Another module, usually the hybrid control module, has stopped receiving messages from drive motor control module "A" over the CAN bus. This module exists on hybrid and electric vehicles and controls the electric motor that drives the wheels, so the vehicle may not enter ready mode or may lose drive power. The cause can be simple, such as a weak small 12-volt auxiliary battery, a connector or a fuse, and several U codes together point to a bus or power problem.

Related codes: U0111U0293P0A80U0100P0562U0001

Symptoms5

• Vehicle does not enter ready mode.
• Hybrid system warning light or check system message on.
• Loss of drive power or very limited power.
• Vehicle stops while driving in some cases.
• Scan tool cannot communicate with the drive motor module.

Possible causes6

• Weak small auxiliary battery that powers the control modules.
• Blown module power fuse.
• Loose or corroded connector at the module or in the communication wiring.
• Poor module ground.
• Inverter overheating from a fault in its cooling system on some vehicles.
• Internal failure of the module or the inverter assembly.

How to diagnose6

1. Read codes from all modules; if many modules report lost communication, start with the battery and the bus, and if only the drive motor control module is missing, focus on it.
2. Try to communicate with the drive motor control module directly with a scan tool; no response points to lost power, ground or wiring to it.
3. Locate the drive motor control module from the manufacturer information, which on hybrid and electric vehicles is usually part of the inverter assembly, and its design varies by make, then check its power fuse and measure power and ground at its connector.
4. Inspect the module connector for water, corrosion or loose terminals, and check the bus wiring to it.
5. Disconnect the battery and measure resistance between the CAN bus wires at the module connector, comparing with the manufacturer specification to find an open or short.
6. Do not disconnect or touch the orange cables or high-voltage parts; testing and repair need a technician trained on hybrid and electric vehicles.

How to fix6

1. Charge or replace the battery, and clean and tighten its terminals.
2. Replace the blown fuse after finding why it blew.
3. Clean the module connector and repair the ground or damaged bus wiring.
4. Update the module software if the manufacturer has an update.
5. Replace the drive motor control module if proven faulty with good power and bus wiring, then program and code it to the vehicle.
6. Clear codes in all modules and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low for the auxiliary battery, a fuse or a connector, and rises sharply if the complete inverter assembly must be replaced and programmed.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions