U0100 on Chevrolet
Lost Communication with ECM/PCM
U0100 on Chevrolet vehicles indicates lost communication with ecm/pcm. Au7o has documented this code across 2 Chevrolet models — most commonly on Blazer, Equinox EV. 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. Typical repair costs on Chevrolet range from $200 to $500, depending on the specific model and root cause.
Common Causes of U0100
- •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
U0100 on Chevrolet by Model
Chevrolet Blazer(1 issue)
- Auto Start-Stop Battery Degradation and System Faults2019-2025
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.
Chevrolet Equinox EV(1 issue)
- Infotainment and Vehicle Software Glitches Requiring Reboot2024-2025
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.
Looking for U0100 on a different make?
View U0100 across all makes →Frequently Asked Questions
What does U0100 mean on 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 specifically, this code is documented across 2 models.
What causes U0100 on Chevrolet vehicles?▼
Common causes on Chevrolet: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix U0100 on a Chevrolet?▼
Repair costs on Chevrolet range from $200 to $500, depending on the specific model and root cause.
Which Chevrolet models have U0100 documented?▼
Au7o has documented U0100 on 2 Chevrolet models: Blazer, Equinox EV.