U0077: Control Module Communication Bus E Off
What Does U0077 Mean?
U0077 is a diagnostic trouble code indicating: Control Module Communication Bus E Off. This code relates to the network communication system. It has been reported in NHTSA complaints across 1 different vehicle models.
Symptoms of U0077
- ⚠️ Traction control system activated
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"INTERMITTENT WHEN DRIVING THE "SERVICE STABILITRAK" MESSAGE APPEARS, AND TRACTION CONTROL/ STABILITY CONTROL IS DISABLED INTERMITTENTLY WHEN STARTING THE "SERVICE STABILITRAK" MESSAGE APPEARS, AND TRACTION CONTROL/ STABILITY CONTROL IS DISABLED CODE READER RETURNS MESSAGE U0077. *TR"
— Gmc Canyon owner, 06/26/2020
Source: NHTSA Complaints Database
Most Reported Vehicles for U0077
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | GMC CANYON |
Frequently Asked Questions
What causes communication codes?
Can a bad battery cause network codes?
What To Do Next
Possible Fixes
- 🔧 Have the code scanned with a professional-grade scanner to read freeze frame data
- 🔧 Check battery voltage and ground connections; inspect CAN bus wiring
- 🔧 If DIY repair isn't feasible, get a diagnostic from a trusted mechanic ($50-150)
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.