U0073

Critical

Control Module Communication Bus Off

Network/Communication System

What Does U0073 Mean?

The entire CAN bus network has stopped communicating. Major system failure.

Common Fix

Repair CAN bus wiring

Estimated Cost (DIY)

$50 - $500

Symptoms

  • ⚠️Multiple warning lights
  • ⚠️No start
  • ⚠️All gauges dead
  • ⚠️No scan tool communication

Related Symptoms

Car won't start

Common Causes

CAN bus wiring short or openlikely
Failed module pulling bus downpossible
Water damage to wiringpossible

How to Diagnose U0073

  1. 1Check CAN H and CAN L wiring
  2. 2Unplug modules one at a time to find the one pulling the bus down
  3. 3Check for water intrusion
  4. 4Inspect main wiring harness

OEM Diagnostic Flowchart

Scroll to load technician if/then branches.

U0073 requires a scanner that reads network modules — basic code readers won't see it.

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Related Resources

Repair guides, symptom pages, and wiring diagrams related to U0073.

OEM Manual Evidence

Browse →
2013 GMC Truck Acadia FWD V6-3.6L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Acadia FWD V6-3.6L Service Manual | Operation CHARM Operation CHARM : Car repair ma...

2013 GMC Truck Acadia AWD V6-3.6L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Acadia AWD V6-3.6L Service Manual | Operation CHARM Operation CHARM : Car repair ma...

2013 GMC Truck Savana 1500 RWD V6-4.3L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Savana 1500 RWD V6-4.3L Service Manual | Operation CHARM Operation CHARM : Car repa...

2013 Chevy Truck Traverse AWD V6-3.6L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 Chevy Truck Traverse AWD V6-3.6L Service Manual | Operation CHARM Operation CHARM : Car repai...

Related Symptoms

Browse →
Car won't startSymptom Hub

No-crank and no-start complaints usually resolve into battery, starter, alternator, crank sensor, or fuel-delivery diagnosis.

Exact Vehicle Hubs

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2013 Chevy Truck Traverse Awd V6 3.6l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to U0073.

2013 Gmc Truck Acadia Awd V6 3.6l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to U0073.

2013 Gmc Truck Acadia Fwd V6 3.6l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to U0073.

2013 Gmc Truck Savana 1500 Rwd V6 4.3l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to U0073.

Related Codes

U0100: Lost Communication with ECM/PCMRelated

A module has lost CAN bus communication with the engine control module.

U0101: Lost Communication with TCMRelated

Communication lost between the ECM and transmission control module.

Frequently Asked Questions

What causes the entire CAN bus to fail?
Usually a shorted wire or a failed module that pulls the entire bus voltage to ground. Water damage is another common cause.
How do I diagnose a CAN bus issue?
Measure CAN H and CAN L voltages with a multimeter. They should be ~2.5V and ~2.5V (inverted). If both are at 0V or 5V, there is a short.

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