U0070
Communication Bus \"B\" Performance
The secondary communication bus (Bus B, often a chassis or comfort sub-bus) shows reduced performance — high error rate, intermittent dropouts, or framing errors. Bus is still alive but unreliable.
The secondary communication bus (Bus B, often a chassis or comfort sub-bus) shows reduced performance — high error rate, intermittent dropouts, or framing errors. Bus is still alive but unreliable.
Common causes
- high
Marginal wiring or corroded connector
One of the most commonly reported causes for this code — check this first.
Typical part cost: $90-1320
- medium
EMI interference (aftermarket equipment)
A plausible cause — test and verify before replacing parts.
Typical part cost: $90-1320
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does U0070 mean?
U0070 means "Communication Bus \"B\" Performance". It is a generic OBD-II code that points to a fault in the network / communication.
What are the most common causes of U0070?
marginal wiring or corroded connector; emi interference (aftermarket equipment); gateway module routing can messages incorrectly — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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