U0401Network Communication

Invalid Data Received From ECM/PCM

U0401 means a module received invalid or implausible data from the engine/powertrain control module over the CAN bus. It can stem from a failing sensor, a software issue, or a wiring problem affecting the ECM's data.

🚗 Not recommended. Invalid data from the engine computer can cause poor running or drivability faults.

HIGH

severity

🎯 Top Causes, Ranked by Likelihood

#1Underlying ECM/PCM sensor or driveability fault$100-$600

40%

A fault in the ECM's inputs produces invalid data on the bus.

#2Wiring or connector fault$50-$500

30%

Bus wiring problems corrupt the data being sent.

#3Software or module fault$100-$1200

20%

Outdated software or a failing ECM sends bad data.

🩺 Common Symptoms

Drivability problems
Multiple warning lights
Erratic gauges
Other U-codes and P-codes stored
Reduced power

💰 Repair Cost: DIY vs Shop

DIY Cost

$50-$400

Shop Cost

$150-$900

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose U0401

1Scan for stored P-codes at the ECM first and address them

2Inspect CAN wiring and connectors for faults

3Check for ECM/PCM software updates

4Verify the ECM's sensor inputs read plausibly

❓ Frequently Asked Questions

Can I drive with U0401?

Not recommended. Invalid engine data can cause poor running. Diagnose it first.

What causes U0401?

Often an underlying ECM fault or sensor problem producing bad data, or wiring issues on the bus.

Should I fix other codes first with U0401?

Yes. Address any P-codes at the ECM first, since they often cause the invalid data this code reports.

🔗 Related Codes

U0100U0402U0300U0140