⚡ AUTO CODE FIX
🔍
Network / CANCritical⚠️ Professional Recommended

U0121

Lost Communication With ABS Control Module

Network communication lost with the ABS module.

SeverityCritical
CategoryNetwork / CAN
Est. Repair Cost$300–$1200
Code TypeNetwork
DIY RepairProfessional

⚡ Common Causes

⚠️ Symptoms

✅ How to Fix — Step by Step

  • Step 1:Check ABS module fuse
  • Step 2:Inspect wiring and connectors
  • Step 3:Test CAN bus
  • Step 4:Replace ABS module
💡 Pro Tip: ABS module communication faults can sometimes be resolved by cleaning the module connector.

Repair Cost Estimate

Full Repair Estimate
$300–$1200
DIY Possible?
PRO
Severity
Critical

Frequently Asked Questions

What does OBD2 code U0121 mean?+
U0121 stands for Lost Communication With ABS Control Module. Network communication lost with the ABS module.
What causes code U0121?+
Faulty ABS module; CAN bus fault; Blown fuse; Poor connector; Battery issue
How do I fix code U0121?+
Check ABS module fuse; Inspect wiring and connectors; Test CAN bus; Replace ABS module
How much does it cost to fix U0121?+
Estimated repair cost for U0121 is $300–$1200.
Is U0121 DIY-friendly?+
U0121 typically requires professional equipment and a qualified mechanic.

AI Diagnosis

Related Codes

P0600Serial Communication Link Circuit
Critical
U0001High Speed CAN Communication Bus
Critical
U0100Lost Communication With ECM/PCM
Critical
U0101Lost Communication With TCM
Critical
U0155Lost Communication With Instrument Panel Cluster
Moderate
U0140Lost Communication With Body Control Module
Moderate