U0100: Lost Communication with ECM/PCM
11 vehicles · 5 makes · $80-$3,500 repair
Most Reported On
U0100 is an OBD-II diagnostic trouble code meaning “Lost Communication with ECM/PCM.” U0100 is a network communication code meaning a module has lost communication with the engine control module / powertrain control module (ECM/PCM) over the vehicle's data bus. The ECM/PCM is the brain that runs the engine, so when other modules can no longer 'talk' to it, the effects can be serious — a no-start, stalling, multiple warning lights, and many other modules logging faults at once. This is almost always a wiring, connector, power/ground, or bus fault, or a failure of the ECM/PCM itself, rather than a single sensor. It should be diagnosed promptly because the vehicle may be undrivable. This code is most commonly reported on 2011-2013 Ford Fusion, 2000-2008 Jaguar S-TYPE, and 2022-2024 Jeep Grand Wagoneer, plus 8 other vehicles, with repair costs ranging from $80 to $3,500.
Common Causes
Typical Repair Cost
Based on 13 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose U0100, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
Vehicles Affected (11)
MyLink / HMI Infotainment Module Failure (U0028 Blank Screen, No Audio/Camera)
Auto Start-Stop Battery Degradation and System Faults
Infotainment and Vehicle Software Glitches Requiring Reboot
Electric Power Steering Rack Failure (Recall 15V340)
Instrument Cluster / Speedometer Erratic Readings and Gauge Dropout
Electric Power Steering (EPAS) Assist Loss / Steering Fault Warnings
12V Battery Drain Causing No-Start and Dead Vehicle
Trailer brake controller / integrated trailer brake module malfunction
Electric power steering (EPS) assist loss / reduced assist warnings (new body style)
Multiple Warning Lights with Speed Limited to 36 MPH
FAQ
What does U0100 mean?
U0100 stands for "Lost Communication with ECM/PCM." U0100 is a network communication code meaning a module has lost communication with the engine control module / powertrain control module (ECM/PCM) over the vehicle's data bus. The ECM/PCM is the brain that runs the engine, so when other modules can no longer 'talk' to it, the effects can be serious — a no-start, stalling, multiple warning lights, and many other modules logging faults at once. This is almost always a wiring, connector, power/ground, or bus fault, or a failure of the ECM/PCM itself, rather than a single sensor. It should be diagnosed promptly because the vehicle may be undrivable.
What are the most common causes of U0100?
The most common causes of U0100 are: Loss of power or ground to the ECM/PCM, CAN bus wiring damage, short, or open circuit, Corroded, loose, or damaged connectors at the module, Blown fuse feeding the ECM/PCM, Failed ECM/PCM, Another faulty module pulling down the data bus, Water intrusion or corrosion in a connector/harness. The specific cause varies by vehicle.
How much does it cost to fix U0100?
Repair costs for U0100 range from $80 to $3,500, depending on the vehicle and root cause.
Which vehicles are affected by U0100?
Au7o has documented U0100 across 11 vehicle models from 5 manufacturers: Chevrolet, Ford, GMC, Jaguar, Jeep.
Sources (12)
- mediaFord Preliminary Evaluation PE14030: EPS failure 2010 Fusion - CarComplaints
- media2010 Ford Fusion Power Steering Assist Fault - CarComplaints
- ForumSilveradoSierra: 2024 HD Trailer Brakes Disconnecting
- ForumGM-Trucks: 2024 Brake controller Problems
- ForumGrand Design Owners: Brake controller issues on 2024 GM HD trucks
- ForumDuramax Forum: 2024 HD trailer brake controller recall
- ForumSilveradoSierra: Electric Power Steering
- mediaZehl & Associates: 800,000 Chevrolet Silverado and GMC Sierra Trucks for Faulty Power Steering
- mediaAboutLawsuits: GMC Sierra, Chevy Silverado Recall Issued Due to Electric Power Steering Problems
- ForumSilveradoSierra: Loss of all power steering 2019 sierra elevation 5.3
- owner-reportCarComplaints.com — Ford Transit problem listings (owner-reported issues; check steering/EPS-related entries by model year)
- owner-reportHummer EV System Issues — HummerChat.com
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.