U0401: Invalid data received from the engine control module (ECM/PCM)
Another module is receiving impossible or inconsistent data from the engine ECU. Usually a faulty engine sensor or a software mismatch is behind it.
| Code | U0401 |
|---|---|
| System | Communication network |
| Group | U04xx, Invalid data between control units |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What U0401 means
The engine ECU (ECM or PCM) shares data such as revs, load, temperature and throttle position over the network. This code is stored by another module, for example the gearbox or ABS unit, when messages arrive but with out-of-range values or errors. The engine ECU often has its own codes that explain the source.
Most common causes
- A faulty engine sensor whose reading is passed on (check the P codes stored at the same time)
- Low or unstable battery voltage
- Loose or corroded engine ECU connector
- Interference or damaged network wiring
- Engine ECU with the wrong software, for example after replacement or reprogramming
- Faulty engine ECU
Symptoms
- Engine or other warning lights on
- Harsh shifts or gearbox in limp mode
- Stability control or cruise control disabled
- Strange readings on the dashboard gauges
Can you drive with U0401?
With care You can drive with care, but the car may go into limp mode or lose some aids. Have it checked soon.
Open the bonnetthe in-depth explanation
How to check it
Read codes from every module, not just this one: engine P codes usually point to the sensor at fault. If the ECU has recently been replaced or reprogrammed, tell the garage.
How to read and clear U0401 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see U0401 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- U0400 Invalid data received
- U0402 Invalid data received from the transmission control module
- U0403 The transfer box control unit is sending data that cannot be used
- U0404 The gear gearbox control unit is sending data that cannot be used
- U0405 The cruise control unit is sending data that cannot be used
- U0415 Invalid data received from the ABS control module
- U0416 Invalid data received from the vehicle dynamics control module
- U0422 Invalid data received from the body control module
What does code U0401 mean?
The engine ECU (ECM or PCM) shares data such as revs, load, temperature and throttle position over the network. This code is stored by another module, for example the gearbox or ABS unit, when messages arrive but with out-of-range values or errors. The engine ECU often has its own codes that explain the source.
Can you drive with U0401?
You can drive with care, but the car may go into limp mode or lose some aids. Have it checked soon.
How do you clear U0401?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, U0401 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
