How much does it cost to fix U0100?

Typical repair cost is $100–$1,500.

U0100 — Lost Communication with ECM/PCM

High Severity · Network

OBD-II code U0100 means your vehicle's ECU detected: Lost Communication with ECM/PCM. Below: causes, step-by-step fixes, and repair cost — free, no signup needed.

High severity — do not ignore. Get a diagnosis promptly to avoid further engine damage.

Typical Repair Cost

$100–$1,500

Parts + labor, national average

Severity

High

Address as soon as possible

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Common Causes of U0100

CAN bus wiring fault
Failed ECM/PCM
Bad ground or power to ECM

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How to Fix Code U0100

Check ECM/PCM power and ground

Inspect CAN bus wiring

Test/replace ECM

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FAQ — Code U0100

What does OBD-II code U0100 mean?

U0100 means your vehicle's onboard computer detected: Lost Communication with ECM/PCM. This is a high-severity code in the Network category.

How much does it cost to fix code U0100?

Typical repair cost for U0100 is $100–$1,500 including parts and labor. Costs vary by vehicle make, model, and location. A free scan at AutoZone or O'Reilly is a good first step.

Can I drive my car with code U0100?

Code U0100 is high severity. Avoid long drives until diagnosed — continued driving can cause additional engine damage.

What are the most common causes of U0100?

The most common causes are: CAN bus wiring fault, Failed ECM/PCM, Bad ground or power to ECM. Always start with the cheapest diagnosis step before replacing parts.

Will code U0100 clear itself?

Code U0100 will clear itself after the underlying issue is fixed and the ECU completes several successful drive cycles. Clearing it without fixing the root cause only masks the problem temporarily.

Is U0100 showing on your car?

Enter your VIN for a free vehicle-specific report — recalls, specs, and market value. No signup required.

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OBD-II code data is based on SAE J2012 standards and general repair industry data. Repair costs are national averages and vary by vehicle, location, and shop. Always consult a qualified mechanic for a diagnosis specific to your vehicle.