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Code result

U01BD

Lost Communication With DC/DC Converter Control Module C

High severity

What it means

ECU lost communication with DC/DC converter module C (steps HV battery down to 12V on hybrids/EVs). 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.

Is it safe to drive?

No — stop driving

This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.

Most likely causes

  • Module unpowered

    high

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

  • Gateway module routing CAN messages incorrectly

    low

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

  • CAN terminating resistor (120 Ω) drifted out of spec

    low

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

Related help

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