Open or shorted wiring in the CAN bus circuit between the active vibration control module and the network; Failed active vibration control module, often due to internal circuit board damage or water intrusion; Blown fuse or poor ground connection supplying power to the active vibration control module; Corroded or loose connector pins at the module or at a CAN bus splice point; Faulty CAN bus termination resistor within the module affecting network voltage levels; A separate module on the same CAN segment pulling the bus down and disrupting communication

DTC codes / U01xx · Lost communication with a control module / U012C

U012CLost Communication With Active Vibration Control Module

Q: What does code U012C mean?

Lost Communication With Active Vibration Control Module. U012C is a network communication code indicating that the engine control module or another primary module has lost the controller area network (CAN) signal from the active vibration control module. The computer detected a complete absence of periodic status messages from that module, not a performance fault within the vibration system itself.

U012C is a network communication code indicating that the engine control module or another primary module has lost the controller area network (CAN) signal from the active vibration control module. The computer detected a complete absence of periodic status messages from that module, not a performance fault within the vibration system itself.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaLost communication with a control module

Symptoms you may notice

Illumination of the malfunction indicator lamp (MIL) or a chassis/suspension warning light
Often no symptoms besides the warning light, with the vehicle driving normally
A noticeable degradation in ride smoothness or increased vibration at idle if the active mounts default to a stiff or fixed state
Multiple unrelated warning lights or communication codes stored in other modules
Intermittent operation of the vibration control system, such as the engine idle smoothing feature cutting in and out

Common causes, most likely first

Open or shorted wiring in the CAN bus circuit between the active vibration control module and the network
Failed active vibration control module, often due to internal circuit board damage or water intrusion
Blown fuse or poor ground connection supplying power to the active vibration control module
Corroded or loose connector pins at the module or at a CAN bus splice point
Faulty CAN bus termination resistor within the module affecting network voltage levels
A separate module on the same CAN segment pulling the bus down and disrupting communication

How to diagnose and fix it

Connect a scan tool and record all stored codes in every module to confirm U012C is current and not history
Check the fuse and ground circuit for the active vibration control module using a wiring diagram and a multimeter
Inspect the module connector and CAN bus wiring for corrosion, chafing, or loose pins
Measure CAN bus voltage and resistance at the module connector to verify the network is intact
Perform a voltage drop test on the module power and ground circuits under load
Substitute a known-good module of the same part number to confirm the fault follows the module
Clear codes and perform a network communication self-test to verify the repair

When the vibration module is not the culprit

A dead battery or low voltage during cranking can set U012C as a history code without any real module fault, so always check battery health first.
The active vibration control module often shares a CAN segment with other chassis modules, and a single failed module on that segment can mimic a vibration module failure.
Water intrusion into the module connector or housing is a common cause that visual inspection of the fuse box will never reveal.
After replacing the module, some vehicles require a network configuration or learn procedure, and skipping it will leave U012C stored even with a good part.
The code does not mean the vibration system has failed internally; it only means the module stopped talking, which can happen from a simple blown fuse.

Can I keep driving with U012C?

The vehicle remains safe to drive because the active vibration system is a comfort feature, but avoid long trips until the fault is repaired since degraded engine mounts can increase vibration and wear over time. If the warning light is accompanied by other communication codes or drivability issues, have the vehicle inspected promptly.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.