U0100 on Audi
Lost Communication with ECM/PCM
U0100 on Audi vehicles indicates lost communication with ecm/pcm. Au7o has documented this code across 1 Audi model — most commonly on Q5 Sportback. 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 Audi range from $300 to $2,500, 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 Audi by Model
Audi Q5 Sportback(1 issue)
- Virtual Cockpit Display Failure and Black Screen2021-2026
The Audi Virtual Cockpit digital instrument cluster can experience intermittent black screens, pixelation, or complete display failure. The NVIDIA Tegra processor overheats or the display connection becomes loose. Some units fail from software corruption during OTA updates. The issue leaves drivers without speedometer, fuel gauge, and warning indicators.
Looking for U0100 on a different make?
View U0100 across all makes →Frequently Asked Questions
What does U0100 mean on Audi?▼
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 Audi specifically, this code is documented across 1 model.
What causes U0100 on Audi vehicles?▼
Common causes on Audi: 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 Audi?▼
Repair costs on Audi range from $300 to $2,500, depending on the specific model and root cause.
Which Audi models have U0100 documented?▼
Au7o has documented U0100 on 1 Audi model: Q5 Sportback.