U0110

Code

Generic U — Network/User

Lost Communication With Drive Motor Control Module A

Brand: Generic

Type: U — Network/User

Views: UK: 34 EN: 89 RU: 49

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Drive motor control module (inverter) powered off or faulted
Blown fuse or opened relay for motor controller power or ignition supply
Open, shorted, or high-resistance wiring in CAN bus to motor controller
Corroded or loose connector pins at motor controller or wiring harness
CAN bus termination resistor open or incorrect resistance
CAN high/low shorted to each other, to battery, or to ground

Symptoms

Malfunction indicator lamp (MIL) or network warning illuminated
Reduced or no drive power, limp or fail-safe mode
Drive motor controller does not show on scan tool or returns 'no response'
Multiple network communication DTCs present or intermittent faults
Vehicle may not shift, disable EV drive, or display drivetrain warnings
No live datastream from motor controller (RPM, inverter status, torque)

What to check

Read and record all network and motor-controller DTCs and freeze frame data
Verify battery/resting voltage and charge if low; check for voltage drops during key-on
Inspect fuses and relays that supply the drive motor control module and CAN bus
Visually inspect connectors and wiring at the motor controller and nearby harness for damage or corrosion
Use a scan tool to attempt communication with the motor controller and other modules on the same CAN segment
Measure CAN High and CAN Low voltages with key ON (engine off) at motor controller connector

Signal parameters

CAN bus idle voltages (key ON, no traffic): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (recessive state)
CAN bus dominant state: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ~2.0 V)
Termination resistance: ≈ 60 ohms measured between CAN_H and CAN_L (two 120 ohm terminators in parallel)
Expected communication rate: vehicle-specific (common rates: 125 kbps, 250 kbps, 500 kbps — confirm with wiring diagram)
No response: absence of valid CAN frames from motor controller when queried by scan tool

Diagnostic algorithm

Record all DTCs, freeze frame, and current bidirectional data. Note whether U0110 is active or historical.
Verify battery voltage and key-on power rails. Recharge battery if voltage is low and recheck communication.
Inspect fuses/relays for the drive motor controller power and any bus power supplies; replace or test as needed.
Visually inspect the drive motor controller connector and harness for damage, pin push-out, corrosion, or water ingress.
With connector connected and key ON, measure CAN_H and CAN_L at the motor controller connector; compare to expected ranges.
Measure resistance between CAN_H and CAN_L with power off; confirm ≈60 ohms. If open or very high, trace for missing terminator.
If voltages/resistance are abnormal, isolate wiring sections: disconnect suspected branches and re-measure to locate open/short.
Use an oscilloscope on CAN_H and CAN_L to view waveform integrity and noise while attempting communication with a scan tool.
If wiring and bus are good but module does not respond, verify power and ground pins at the module under load. Wiggle test for intermittent faults.
If available, swap in a known-good drive motor control module or use a bench-tested unit following manufacturer safety and programming procedures (only if qualified).
Clear codes and perform a road or functional test to confirm repair. If intermittent, monitor for recurrence and inspect related modules/devices that share the bus.
Safety note: Drive motor controllers are often part of high-voltage systems. Do not perform internal HV component repairs unless trained and equipped. Isolate high-voltage system per manufacturer procedures before servicing.

Likely causes

Blown power fuse or failed contactor/relay supplying the drive motor controller
Connector contamination or pin pushed out at the motor controller
Broken CAN-H or CAN-L wire near motor or chassis harness entry
Failed drive motor control module (internal communication circuit)
Open/miswired CAN termination (missing 60 ohm total)
Short to chassis ground on CAN low or to battery on CAN high

Fault status

⚠️ Status

No communication received from Drive Motor Control Module A on the vehicle network. The fault may be active (current) or stored. Check power, grounds, connectors, and CAN bus integrity before replacing the module.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1.0-4.0 hours