U0101High urgency

Lost Communication with Transmission Control Module

Network · CAN Bus

⛔ Fix promptly — transmission may not shift correctly.

What this means

The engine control module cannot communicate with the transmission control module. Loss of communication causes the transmission to enter a fail-safe mode, often staying in one gear.

Likely causes

Failed TCMMost common
CAN bus wiring fault between ECM and TCMCommon
Blown fuse to TCMCommon
Corroded TCM connectorCommon

Estimated repair cost

TCM replacement and programming$400 – $1,500

Wiring repair$150 – $500

Fuse/connector repair$20 – $150

🏪

Frequently asked questions

What does U0101 mean?

The engine control module cannot communicate with the transmission control module. Loss of communication causes the transmission to enter a fail-safe mode, often staying in one gear.

Is U0101 serious?

Fix promptly — transmission may not shift correctly.

How much does it cost to fix U0101?

Repair costs for U0101 range from $400 – $1,500 depending on the root cause and your vehicle.

Can I drive with U0101?

No — this code indicates a serious issue. Stop driving and have the vehicle inspected immediately.