OBD-II Network Error Code U0121: How to Fix It

Q: Can I drive with U0121 error code?

You can drive short distances at low speeds, but your ABS, traction control, and stability control systems may not work properly. Avoid highway driving and get the issue diagnosed immediately as it affects vehicle safety.

Q: What causes U0121 error code?

Common causes include blown ABS fuses, corroded electrical connections, damaged wiring, failed ABS module, or problems with the vehicle's CAN bus communication network.

Q: How much does it cost to fix U0121?

Costs range from $20 for a blown fuse to $500-1500 for ABS module replacement. Most issues involving wiring or connections cost $100-400 to repair at a shop.

Q: Will U0121 cause my brakes to fail?

No, your regular brakes will still work normally. However, the anti-lock brake system, traction control, and electronic stability control features will be disabled, reducing safety in emergency braking situations.

Q: Can a bad battery cause U0121?

Yes, a weak or failing battery can cause communication errors like U0121. Low voltage can disrupt the CAN bus network communication between modules. Check battery voltage first if you have multiple communication error codes.

Abstract

Error code U0121 indicates your vehicle's computer has lost communication with the Anti-Lock Brake System (ABS) module. This is a serious safety issue that can disable your ABS and other brake-related safety features like traction control and stability control.