U0401Invalid Data Received From ECM/PCM A
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U0401 is stored by a module that keeps receiving the engine or powertrain controller's messages but finds their content faulty. Most often the transmission controller logs it; Ford's 2012 OBD summary names engine torque and pedal position as the data concerned. In GM's 2025 tables the TCM checks rolling counter, protection value and checksum of several ECM frames, treats 8 bad results within 18 checks as a failure and classes the code Type A (MIL at once); GM's driver-assist module sets it as Type C and only switches off adaptive cruise. Saab's 2011 code list adds sub-codes 72 (counter) and 74 (checksum). Bentley's Continental GT gearbox stores U040100 when brake pressure decays too fast in ACC stops; a passive entry can stay. Ford's 2020 Escape and GM's 2024 Corvette needed new software. U0100 means lost contact.
- What you may notice
- Check engine light, often stored in the transmission controller
- Harsh shifts or transmission limp-home mode
- Adaptive cruise control switched off
- Likely causes
- LikelySoftware of the ECM/PCM or of the receiving module (update available)
- PossibleECM sends a signal flagged invalid, for example after its own sensor fault
- PossibleDisturbed CAN traffic from connectors, wiring or low battery voltage
- RareEngine control module internally faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.