Invalid Data Received From ECM/PCM
The U0401 code means the vehicle's onboard diagnostic system has detected: Invalid Data Received From ECM/PCM. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $50 - $500 (usually the fault behind the bad data, not the network itself)
Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.
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Common Symptoms
- Check Engine or related warning light on
- Functions relying on data from the ECM/PCM may act erratically
- Often intermittent
Probable Causes (Ranked by Likelihood)
- The ECM/PCM is transmitting, but its data is implausible - often a failing sensor feeding it High
- Intermittent wiring fault corrupting messages Moderate
- Software mismatch after service Moderate
- Failing ECM/PCM Low
Common Fixes by Vehicle
What techs usually find when diagnosing U0401 on specific vehicles — tap your vehicle for the fix and the exact part:
2007-2018 Chevrolet Silverado/GMC Sierra moderate (diagnosis), hard (reflash) DIY
Invalid data received from ECM/PCM means the PCM is communicating on the CAN bus but sending corrupt data. This is usually caused by a PCM software glitch or a failing PCM. Try clearing codes and monitoring. If U0401 returns, the PCM may need a software reflash. GM dealers can check for updated calibrations. If no updates are available, the PCM itself may need replacement.
Labor: 30 min (diagnosis), 2 hours (reflash/replace)2008-2020 Ford F-150/Escape/Explorer easy DIY
U0401 on Ford vehicles can be caused by a PCM that needs a Throttle Body relearn or KAM (Keep Alive Memory) reset after a battery disconnect. Disconnect the battery for 15 minutes, reconnect, then idle the engine for 5 minutes without touching the throttle. This allows the PCM to relearn its adaptive values. If U0401 persists, the PCM may need a software update via IDS.
Labor: 15-30 min
2007-2017 Chevrolet Tahoe/Suburban/Yukon moderate DIY
On GM SUVs, U0401 can appear after installing a tuner or performance programmer that modifies PCM data. If a tuner has been installed, return the PCM to stock calibration and clear codes. If no tuner is present, this code along with drivability issues usually means the PCM needs replacement. GM PCMs must be VIN-programmed after installation.
Labor: 30 min - 2 hoursFrequently Asked Questions
What does U0401 mean?
U0401 means this module IS communicating with the ECM/PCM, but the data it sends fails plausibility checks. Diagnose the source module first.
Can I keep driving with U0401?
Usually yes for a short period. The affected function may be degraded, and intermittent wiring faults tend to worsen - diagnose soon.
Should I replace the module for U0401?
Not first. Most communication codes are power, ground, fuse, or wiring problems. Replace the module only after those test good - modules are expensive and often require programming.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Scan the ECM/PCM itself - the invalid data usually traces to a fault code stored there.
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Fix any codes in the source module first; this code often clears with them.
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Check for recent programming or battery-disconnect events.
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If the source module is clean, monitor the specific data value flagged and follow the OEM pinpoint test.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
U0401 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
Commonly Affected Vehicles
- All OBD-II vehicles - network (U) codes are standardized across makes
Related Codes
See All Codes & Fixes for Your Vehicle
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