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ElectricalSeverity High: diagnose before driving on

U0073Control Module Communication Bus "A" Off

What it means

A control module switched off its communication on bus "A" because of too many errors.

Symptoms

  • Several warning lights
  • Possibly no start

Common causes

  • Short on the CAN bus
  • Faulty module
  • Supply or ground problems

What to check first

  1. Measure CAN resistance and voltages
  2. Scope the bus
  3. Check module supplies and grounds
Can I drive with U0073? Not recommended. U0073 can lead to stalling, limp mode or engine damage; diagnose it before driving further.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

How to test the parts behind U0073

CAN bus networkWiring, typical values, multimeter and scope tests

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U0073: questions and answers

What does U0073 mean?

U0073: Control Module Communication Bus "A" Off. A control module switched off its communication on bus "A" because of too many errors.

What are the symptoms of U0073?

Several warning lights. Possibly no start.

What causes U0073?

Short on the CAN bus. Faulty module. Supply or ground problems.

How do you diagnose U0073?

1. Measure CAN resistance and voltages 2. Scope the bus 3. Check module supplies and grounds

Can I drive with U0073?

Not recommended. U0073 can lead to stalling, limp mode or engine damage; diagnose it before driving further.