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Code result

U0401

Invalid Data Received From ECM/PCM A

High severity

What it means

The ECM/PCM is present on the data bus but the values it reports are implausible — out of range, frozen, or failing the checksum or rolling-count check. The receiving modules reject the data. Implausible engine data can force limp mode or stall the engine. Causes include a faulty sensor feeding the module, internal computation errors, a software or calibration mismatch after a repair, or bus interference corrupting the frames.

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

  • ECM software bug or outdated calibration

    medium

    A plausible cause — test and verify before replacing parts.

  • ECM internal sensor or processing fault

    medium

    A plausible cause — test and verify before replacing parts.

  • CAN corruption causing checksum errors

    medium

    A plausible cause — test and verify before replacing parts.

Related help

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