U0043: Vehicle Communication Bus B (-) Low
System
Network Communication
What Does U0043 Mean?
U0043 is a diagnostic trouble code indicating: Vehicle Communication Bus B (-) Low. This code relates to the network communication system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.
What To Do Next
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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.
Related Codes
U0038
Vehicle Communication Bus B Performance
U0039
Vehicle Communication Bus B (+) Open
U0040
Vehicle Communication Bus B (+) Low
U0041
Vehicle Communication Bus B (+) High
U0042
Vehicle Communication Bus B (-) Open
U0044
Vehicle Communication Bus B (-) High
U0045
Vehicle Communication Bus B (-) shorted to Bus B (+)
U0046
Vehicle Communication Bus C