Control Module Communication Bus A Off
The DURAMAX-U0073 (Duramax) diesel fault code means: Control Module Communication Bus A Off. This is a serious severity code.
Unverified. We could not confirm this code's definition against freely available manufacturer documentation, so treat the meaning, severity and fix guidance on this page as unconfirmed. Check it against the manufacturer's service information for your exact model and serial range before acting on it. This page is kept out of search engines for that reason, and we are working through this family manual by manual.
- Keep driving?
- Yes, with caution
- DIY difficulty
- intermediate
- Estimated cost
- $100-$1,500
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View pilot availability →What Are the Symptoms of DURAMAX-U0073?
- Check Engine Light illuminated
- Performance loss or rough running (if engine-related)
- Warning message on dash (DPF/DEF-related)
- Limp mode under certain conditions
- Possible hard starting or stalling
What Causes DURAMAX-U0073? (Most Likely First)
- Vehicle high-speed CAN bus off — short or open in network Very Likely
- Wiring harness abrasion / connector corrosion Likely
- Sensor end-of-life (high-mileage trucks) Possible
- Related upstream fault (e.g., low battery voltage, ground fault) Possible
Can I Still Drive with DURAMAX-U0073?
Yes, with caution. DURAMAX-U0073 is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What is U0073 on a Duramax?
Duramax code U0073 (Control Module Communication Bus A Off) is a serious-severity diagnostic trouble code triggered by the engine control module when it detects a problem in the associated system. Duramax trucks accumulate soft-fault codes — clear them and retest rather than throwing parts at recurring-but-harmless DTCs.
Is a Duramax U0073 safe to drive?
Depends on severity. Critical codes (fuel pressure, PCM, overtemp) need immediate attention. Sensor codes are usually OK short-term.
How much does it cost to fix U0073 on a Duramax?
Estimated repair cost $100-$1,500. Scan first — cascaded codes often share a single root cause.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose DURAMAX-U0073?
Scan all modules — a single failure often sets codes in multiple modules
Capture freeze frame and compare to known operating ranges
Back-probe the associated sensor/actuator with a DMM
Inspect wiring and connectors at both ends of the affected circuit
Clear code, perform a complete drive cycle, and verify the fault is fixed
U0073 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:
Which Vehicles Commonly Get DURAMAX-U0073?
- 2001-2004 Chevy Silverado 2500/3500 HD 6.6L Duramax LB7
- 2001-2004 GMC Sierra 2500/3500 HD 6.6L Duramax LB7
- 2004.5-2005 Chevy Silverado 2500/3500 HD 6.6L Duramax LLY
- 2004.5-2005 GMC Sierra 2500/3500 HD 6.6L Duramax LLY
- 2006-2007 Chevy Silverado 2500/3500 HD 6.6L Duramax LBZ
- 2006-2007 GMC Sierra 2500/3500 HD 6.6L Duramax LBZ
- 2007.5-2010 Chevy Silverado 2500/3500 HD 6.6L Duramax LMM
- 2007.5-2010 GMC Sierra 2500/3500 HD 6.6L Duramax LMM
- 2011-2016 Chevy Silverado 2500/3500 HD 6.6L Duramax LML
- 2011-2016 GMC Sierra 2500/3500 HD 6.6L Duramax LML
- 2017+ Chevy Silverado 2500/3500 HD 6.6L Duramax L5P
- 2017+ GMC Sierra 2500/3500 HD 6.6L Duramax L5P
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