U012C code meaning
Lost Communication With Active Vibration Control Module
What U012C means
U012C covers the controller that drives active engine mounts or inertial shakers to cancel engine vibration, for example in cars that switch off cylinders. Such a unit needs engine speed and load from the network to generate a counter-phase force; a Honda patent (US 10360893) describes a separate AVC control unit with actuators and acceleration sensors that adapts its cancelling output to engine rotation. No manufacturer publishes a description of U012C itself, so the setting rule is the general one from CARB's network monitoring: the receiving controller stores the code when expected frames stay away. Engine mount actuator wiring has its own codes, P0A14 and following; invalid data is U042D. Expect more cabin vibration, usually no MIL.
U012C at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U012C
- Noticeable engine vibration at idle or in cylinder deactivation mode
- Humming or booming noise in the cabin
- Fuel saving mode may stay disabled
Common causes of U012C
- Most likelyPower or ground of the vibration control unit missing
- PossibleBus wire or connector damaged near engine or subframe
- Less likelyActive vibration control module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Active vibration moduleCAN bus wiring
What each part of U012C means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 2C | The exact fault in that area. |
What to do next
- Note U012C and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U012C
What does U012C mean?
U012C means "Lost Communication With Active Vibration Control Module". U012C covers the controller that drives active engine mounts or inertial shakers to cancel engine vibration, for example in cars that switch off cylinders. It is a generic code, so it means the same on every make.
Is it safe to drive with U012C?
U012C does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U012C fail an emissions test?
U012C is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U012C to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U012C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.