U0053
Vehicle Communication Bus C (-) High
Communication network (CAN bus)
Generic OBD-II
Medium
What it means
U0053 means the voltage on the CAN "low" (-) wire of vehicle communication Bus C has risen above its normal range, garbling data between the modules on that bus. It typically comes from a wire shorted to power, a poor module ground, or a failing module. The car often still drives, but if drivetrain modules share this bus you may see limp mode, so it's best diagnosed without delay.
Medium
Can I keep driving? Often yes, but not guaranteed — abnormal bus voltage disrupts data on this network; if it carries drivetrain modules you could see limp mode, so have it diagnosed promptly.
Common symptoms
What you'll notice
- Warning lights on and several modules reporting communication faults
- Features on Bus C become intermittent or stop working
- Gauge, display, or accessory glitches
- Reduced power or limp mode if the affected bus carries powertrain modules
Common causes
Most likely first
- CAN-low (-) wire shorted to a higher-voltage circuit or to battery powerLikely
- Chafed, pinched, or corroded bus wiring or a faulty connectorCommon
- A failing module biasing the bus voltage highCommon
- Poor module ground, raising its bus voltageLess often
- Water intrusion in a connector or moduleLess often
How to diagnose & fix
Work through it in order
- Scan all modules and record every stored code to map which part of Bus C is affected.
- Inspect the Bus C wiring and connectors for chafing, corrosion, or moisture.
- Measure CAN-high/low voltage against spec to locate the short-to-high.
- Check module grounds; a poor ground can push a module's bus voltage up.
- Disconnect suspect modules one at a time, then repair wiring or replace the faulty module and re-test.
FAQ
Quick answers
Is it safe to drive with U0053?+
Usually the car still moves, but the modules on this bus can't communicate reliably. If warning-light or drivetrain systems share the bus they may misbehave, so get it checked.
Can I just clear U0053?+
It clears, but a genuine short-to-high or failing module brings it back once the bus is used. Fix the underlying fault first.
Related codes
Often seen with U0053
Read & clear U0053 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX