All codes/U301C

U301C

Control Module Wake-up Circuit A High

Moderate severity

Wake-up signal A voltage above expected range — short to power. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.

Wake-up signal A voltage above expected range — short to power. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.

Common causes

  • Wiring shorted to battery

    One of the most commonly reported causes for this code — check this first.

    high

    Typical part cost: $60-440

  • Gateway module routing CAN messages incorrectly

    Less common, but worth ruling out after the more likely causes.

    low

    Typical part cost: $60-440

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First things to check

  1. 1Confirm the code with a scan tool and check for additional related codes.
  2. 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

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Related codes

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Frequently asked questions

What does U301C mean?

U301C means "Control Module Wake-up Circuit A High". It is a generic OBD-II code that points to a fault in the network / communication.

What are the most common causes of U301C?

wiring shorted to battery; gateway module routing can messages incorrectly; can terminating resistor (120 ω) drifted out of spec — 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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