U0122: Lost Communication With Vehicle Dynamics Control Module
Other control units no longer receive messages from the Vehicle Dynamics Module.
High risk
Have it checked soon. Stability control and traction control may not work.
Short answer · Can I keep driving with U0122?
Usually yes, with care. Stability control and traction control may not work. Have the network and the module checked soon.
What does U0122 mean?
Code U0122 means a control unit expected regular messages from the Vehicle Dynamics Control Module on the vehicle network and they stopped arriving. A power or ground fault at that module, a damaged network wire or corroded connector, low battery voltage or a failed module are typical causes.
What the car does when the code is set
Functions that depend on the affected module are switched off. ABS, stability control, cruise control or power steering assistance may be unavailable, with matching warning lights.
How the system works
The ABS control module and power steering module share wheel speed, steering angle and other data over the network. Other modules rely on this data and store a lost communication code when it stops arriving.
Common symptoms
Possible causes
Listed without ranking. The cause on your car depends on make, engine and mileage — see the maker notes below.
- Power or ground fault at the moduleA blown fuse or poor ground switches the module off.
- Connector corrosionModules near the wheels or under the car are exposed to water and salt.
- Damaged network wiringChafed or corroded CAN wires.
- Low battery voltageVoltage dips can cause temporary communication loss.
- Failed moduleLess common than wiring faults.
How it is diagnosed
- Check which warning lights are onABS, stability control or steering warnings show which system is affected.
- Check fuses and battery voltageStart with the simplest causes.
- Inspect the module connectorLook for corrosion and loose pins.Disconnect the battery only as described in the manual; some modules need a relearn afterwards.
- Scan all modulesA workshop checks whether the module responds and tests the network wiring.
Questions about U0122
Can a weak battery cause U0122?
Yes. Low voltage during starting can make modules drop off the network for a moment and store this code. Check the battery before replacing any module.
Do the brakes still work?
Normal braking usually remains, but ABS and stability control may be off. Drive carefully and have it checked.