Lost Communication with ECM/PCM
The Body Control Module (BCM) or another control module has lost communication with the Engine Control Module (ECM) or Propulsion Control Module (PCM) over the CAN bus.
Estimated Cost
$80 – $2,500
Repair Time
1–4 hours
DIY Difficulty
DIY Possible
Can I Fix This Myself?
DIY-Friendly Repair
Many owners resolve this with basic tools at home.
Tools you'll need:
Follow the step-by-step wizard below. If the issue persists after working through all steps, it's time to schedule a professional service appointment.
Check Your Warranty Before Paying
Federal law requires EV battery warranty coverage for 8 years / 100,000 miles minimum. Many manufacturers offer 10-year coverage. An authorized dealership can confirm coverage for your VIN at no charge.
Local EV Specialists Near You
Austin EV Diagnostics
Cybertruck, Model 3/Y, IONIQ 5 & Mach-E Service
Austin, TX
More local specialists
Lone Star EV Repair
Austin, TX · 4.5★
Step-by-Step Diagnostic Wizard
Answer each question to narrow down the root cause of your U0100 fault.
Check 12V Auxiliary Battery
Step 1 of ~7
Measure the 12V auxiliary battery voltage with a multimeter. The 12V battery is in the front compartment on the Bolt EV. A weak 12V battery is the most common cause of U0100 in EVs.
Is the 12V battery voltage above 12.4 V (engine off)?
Need hands-on help?
Find a verified EV mechanic or dealership near you.