⚡ AUTO CODE FIX
🔍
Network / CANCritical⚠️ Professional Recommended

U0100

Lost Communication With ECM/PCM

The vehicle network has lost communication with the engine control module.

SeverityCritical
CategoryNetwork / CAN
Est. Repair Cost$500–$2000
Code TypeNetwork
DIY RepairProfessional

⚡ Common Causes

⚠️ Symptoms

✅ How to Fix — Step by Step

  • Step 1:Check ECM fuses
  • Step 2:Check ECM power and ground connections
  • Step 3:Inspect CAN bus wiring for damage
  • Step 4:Test battery and charging system
  • Step 5:Replace ECM if all else checks out
💡 Pro Tip: Always check fuses and battery before condemning an ECM — low voltage causes false U-codes.

Repair Cost Estimate

Full Repair Estimate
$500–$2000
DIY Possible?
PRO
Severity
Critical

Frequently Asked Questions

What does OBD2 code U0100 mean?+
U0100 stands for Lost Communication With ECM/PCM. The vehicle network has lost communication with the engine control module.
What causes code U0100?+
Faulty ECM/PCM; Damaged CAN bus wiring; Blown ECM fuse; Poor ECM ground connection; Battery voltage issue
How do I fix code U0100?+
Check ECM fuses; Check ECM power and ground connections; Inspect CAN bus wiring for damage; Test battery and charging system; Replace ECM if all else checks out
How much does it cost to fix U0100?+
Estimated repair cost for U0100 is $500–$2000.
Is U0100 DIY-friendly?+
U0100 typically requires professional equipment and a qualified mechanic.

AI Diagnosis

Related Codes

U0101Lost Communication With TCM
Critical
P0600Serial Communication Link Circuit
Critical
U0001High Speed CAN Communication Bus
Critical
U0121Lost Communication With ABS Control Module
Critical
U0155Lost Communication With Instrument Panel Cluster
Moderate
U0140Lost Communication With Body Control Module
Moderate