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TuningBot DTC Database · v4.37.14

U063B Lost Communication With Coolant Bypass Valve Actuator A

Generic (OBD-II) interpretation in the TuningBot DTC database.

U · NetworkNetworkOBD2

What U063B means

U063B
Lost Communication With Coolant Bypass Valve Actuator A Generic · network Data confidence 65%

The control module stopped receiving expected network messages from the Coolant Bypass Valve Actuator A node on the vehicle communication bus.

Symptoms

  • Multiple warning lamps possible
  • Functions of the affected module unavailable

Possible causes

  • CAN bus wiring fault (open, short, chafed harness)
  • Faulty control module loading the bus
  • Connector or terminal corrosion
  • Power supply or ground fault of a module

Recommended checks

  • Perform a full-module scan to map which modules communicate
  • Check CAN bus resistance and voltages at the diagnostic connector
  • Inspect wiring and connectors of the affected module
  • Check module power supply and grounds
  • Disconnect suspect modules one at a time only with a documented procedure

Related and nearby codes

U06 range
U0600U0601U0602U0603U0604U0605U0606U0607U0608U0609U060AU060BU060CU060DU060EU060FU0610U0611

How to read U063B

U

Network: communication between control units.

0

Generic SAE-standard code: same meaning on every make.

63B

Specific fault index within the subsystem.

Frequently asked questions about U063B

What does U063B mean?

Lost Communication With Coolant Bypass Valve Actuator A. The control module stopped receiving expected network messages from the Coolant Bypass Valve Actuator A node on the vehicle communication bus.

Is U063B generic or manufacturer-specific?

U063B is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove U063B at file level?

Not guaranteed. Powertrain (P) codes can be reliably disabled in the ECU calibration, but body, chassis and network codes depend on the specific control unit and how the fault is implemented - some can be handled, some cannot. Ask for a quote and our engineers will check your file and tell you, free of charge, whether U063B is removable in your case.

Other file services

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Understand the system behind this code: Diagnostic Strategy and DTC Logic

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