U0021 OBD-II: Low Speed CAN Communication Bus (+) Open

U0021 Severity

Moderate

Will U0021 go away on its own?

Once the vehicle's onboard system no longer detects the issue, most codes will disappear on their own. If your vehicle still has this code, however, it should be properly diagnosed to avoid a more serious problem.

For a proper diagnosis, RepairPal Certified shops have the equipment, tools, and expertise.

Moderate severity codes might not threaten the vehicle's safety or functionality immediately, but you should still get it diagnosed within a reasonable time frame to keep your car running well.

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OBD II Fault Code

OBD II U0021

OBD-II Code Diagnostic Trouble Code is defined as a Low Speed CAN Communication Bus (+) Open

OBD Code Resources

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U0021 OBD-II: Low Speed CAN Communication Bus (+) Open

Will U0021 go away on its own?

Need a U0021 diagnosis? Trust our experts.

OBD II Fault Code

OBD Code Resources

Need a U0021 diagnosis? Trust our experts.

Ask our experts about U0021.

Other OBD-II Codes

OBD II Fault Code