U0100 on Chevrolet: How to Diagnose & Fix
Lost Communication with ECM/PCM
5 Chevrolet models · 5 documented issues · 1 critical · $150-$1,500 repair
U0100 on Chevrolet by model: symptoms, diagnosis and fix
The MyLink infotainment system on 2013-2018 Camaros can suddenly go to a blank/black screen with total loss of audio, touchscreen, and backup-camera functions. The typical stored code is U0028 (communication bus / serial data fault), pointing at the HMI (Human-Machine Interface) module, the central computer of the MyLink system. Voltage spikes from a dead/replaced battery or a jump-start commonly damage the HMI. Beyond the loss of features, the fault can keep modules awake and cause a parasitic battery drain. GM technical bulletin PIC6073E addresses U0028 on this platform.
Common Symptoms
- Black or blank infotainment screen
- No audio from the radio
- Backup camera not displaying
- Unresponsive touchscreen
- U0028 stored code
- Battery drain / dead battery overnight
How to Fix
Start with a soft reset (hold Home + fast-forward ~10 seconds until the screen goes dark). If the screen stays blank and U0028 is stored, the fix is usually HMI module replacement; the module is VIN-locked and must be programmed by a dealer or a specialized module shop. Check for chafed/corroded wiring and ensure a healthy battery to avoid repeat failures. A rebuilt/programmed exchange HMI is a lower-cost path.
Sources for this issue (1)
The AGM battery required for the auto start-stop system degrades prematurely, often failing within 2-3 years. When the battery weakens, the start-stop system disables itself and various electrical warnings appear. The auxiliary battery (on equipped models) can also fail, compounding the issues.
Common Symptoms
- Start-stop system not functioning
- Battery warning messages
- Multiple warning lights on startup
- Slow cranking
- Electrical accessories resetting
How to Fix
Replace the AGM battery with a genuine ACDelco AGM battery — standard flooded batteries are not compatible with the start-stop system. After replacement, a battery sensor reset via a scan tool is required. Some owners permanently disable start-stop with aftermarket modules if they find the feature annoying.
Sources for this issue (1)
The factory negative battery cable was crimped with insufficient force at the battery terminal clamp. Over time the crimp oxidizes and internal resistance climbs, so the whole vehicle ground becomes marginal. The symptom set is famously scattershot: flickering lights, radio and HVAC display cycling off and on, phantom ABS / StabiliTrak / Service Steering messages, 'Battery Saver Active', no turn-signal chime, and eventually a no-crank where the lights work and the starter solenoid clicks but the engine won't turn over. Owners frequently replace batteries and starters before finding it. GM issued Special Coverage 14311 extending coverage to 10 years / 120,000 miles.
Common Symptoms
- No crank, solenoid clicks, lights stay on
- Radio and HVAC display turning off and on
- Service StabiliTrak / Service Traction / Service Steering messages
- Battery Saver Active message
- Interior and exterior lights flickering
- Repeat battery replacements that don't fix it
How to Fix
Do a voltage-drop test across the negative cable from battery post to engine/body ground while cranking - more than roughly 0.2V indicates the bad crimp. Cutting and re-terminating rarely holds; replace the complete negative battery cable assembly with the updated GM part and clean the body and transmission ground points. Check VIN eligibility under Special Coverage 14311 first.
Sources for this issue (3)
C8 owners across several model years report that the car's control modules do not enter sleep after shutdown, leaving the radio, infotainment screen and instrument cluster powered up with the vehicle off. The battery is drained overnight and the car will not restart. NHTSA complaints document both halves of this: a 2024 owner reported the radio, infotainment screen and instrument cluster had failed to turn off and the vehicle subsequently failed to restart, and a 2022 owner reported battery drain causing a no-start that required disconnecting the negative battery terminal to reset the modules and clear stored codes. On the C8 this is more than an inconvenience — the battery lives in the rear compartment and a fully dead battery can leave the doors, which are electrically released, difficult to open, and it can force manual release procedures. Cars that sit between drives, which describes most Corvettes, are disproportionately affected.
Common Symptoms
- Infotainment screen, radio and cluster remain on after shutdown
- Battery flat after the car sits overnight or a few days
- Vehicle fails to restart
- Multiple spurious stored fault codes
- Electric door release inoperative with a dead battery
- Condition temporarily cleared by disconnecting the negative terminal
How to Fix
If the screens stay lit after you walk away, that is the diagnostic — the car is not sleeping and the battery is being consumed. Have a dealer perform a proper parasitic draw test after allowing full module sleep time (typically 45 minutes or more, not a quick reading), and have them check for available module software updates, since sleep-state faults on this platform are commonly a calibration issue rather than a failed component. Do not simply keep replacing batteries. In the meantime, keep a quality battery maintainer on the car whenever it sits more than a few days — GM recommends this for the C8 regardless. Learn and practice the manual door release procedure before you need it, because a flat battery on this car locks you out of the normal electric door buttons. Disconnecting the negative terminal will reset the modules and clear the condition temporarily, but it will return until the underlying draw is found.
Sources for this issue (2)
As a first-model-year EV on GM's Ultium platform, the Equinox EV experiences various software glitches including infotainment freezing, incorrect range estimates, phantom driver assistance warnings, and occasional 12V auxiliary battery management issues. These are typical new-platform teething problems.
Common Symptoms
- Infotainment screen freezes or goes black
- Incorrect range estimate
- False collision warnings
- Vehicle fails to enter Ready mode
- 12V battery drain overnight
How to Fix
Keep the vehicle software updated via OTA updates — GM is actively pushing fixes. Perform a vehicle reset by parking, locking, and waiting 5 minutes before restarting. For persistent issues, the dealer can perform a full system reflash. The 12V battery may need replacement if it was drained by a software bug.
Sources for this issue (1)
U0100 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U0100 mean on a Chevrolet?
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. On Chevrolet it is documented across 5 models: Camaro, Blazer, Cruze, Corvette, Equinox EV.
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 on a Chevrolet?
Published repair estimates on Chevrolet range from $150 to $1,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for U0100 on a different make?
View U0100 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.