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TuningBot DTC Database · v4.37.14

U301B Control Module Wake - up Circuit A Low

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

U · NetworkNetworkOBD2

What U301B means

U301B
Control Module Wake - up Circuit A Low Generic · network Data confidence 65%

The control module detected a fault associated with the Control Module Wake - up Circuit A Low circuit or function; the stored code identifies the affected component rather than a single failure mode.

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

How to read U301B

U

Network: communication between control units.

3

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

01B

Specific fault index within the subsystem.

Frequently asked questions about U301B

What does U301B mean?

Control Module Wake - up Circuit A Low. The control module detected a fault associated with the Control Module Wake - up Circuit A Low circuit or function; the stored code identifies the affected component rather than a single failure mode.

Is U301B generic or manufacturer-specific?

U301B is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove U301B 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 U301B is removable in your case.

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