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Trouble code libraryNetwork and modules

U0073 Control module communication bus A off

Code familyModules aren't talking to each other

Short trips onlyDrive it only if you have to, gently and not far. Get it fixed right away.

Check this first

Check the battery terminals and grounds first – weak power causes most network codes.

What usually fixes it

In the order a good shop checks them. Typical total: $114–$1,906 at $130 an hour.

  1. Battery, terminals and grounds

    $114–$512

    Low voltage drops modules off the network.

  2. Network wiring

    $258–$725

    A damaged wire between modules.

  3. Failed module

    $660–$1,906

    One module that has stopped answering.

This is the advice for this family of codes – Drive DTC doesn't have advice written for U0073 on its own yet.

Code titles are the generic SAE definitions. Prices are typical US parts and labor for a common car or light truck – a guide for judging a quote, not a quote. Always confirm a repair against the vehicle in front of you.

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See what your vehicle says about U0073

A stored code is a headline, not the story. The vehicle also holds the conditions from the moment the code set, how close each part is to the limit it fails at, what the fuel trims are doing, and whether the fault is still happening. Drive DTC reads all of it with a USB adapter and a Windows PC – read-only by design.

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Diagnose · Trouble codes
The Trouble codes screen in Drive DTC: stored, pending and permanent counts, then C0040-13 explained in plain English with what to check first, likely fixes in order and typical cost ranges

More in Network and modules

All 8 codes in this group
U0100Lost communication with ECM/PCM A U0101Lost communication with TCM U0121Lost communication with anti-lock brake system (ABS) module U0140Lost communication with body control module U0151Lost communication with restraints control module U0155Lost communication with instrument panel cluster (IPC)