U0401 – Invalid data received – engine control module (ECM)
Last Updated 2017-08-26
Automobile Repair Shop Owner
|Code||Fault Location||Probable Cause|
|U0401|| Invalid data received - engine control module (ECM) |
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|Wiring, Abnormal system voltages, Defective engine and driveability sensors|
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Table of Contents
- What Does Code U0401 Mean?
- Where is the U0401 sensor located?
- What are the common causes of code U0401?
- What are the symptoms of code U0401?
- What are common solutions to code U0401?
- How serious is code U0401?
- How safe is it to still drive the car with code U0401?
- How difficult is it to repair code U0401?
- What are the common mistakes when repairing code U0401?
- How do you troubleshoot code U0401?
- Codes Related to U0401
- Get Help with U0401
What Does Code U0401 Mean?
OBD II fault code U0401 is a generic code that is defined as “Invalid data received – engine control module (ECM), but sometimes as “Invalid Data Received from ECM (Engine/Electronic Control Module) /PCM (Powertrain Control Module) “A””, and is set when a communication fault occurs between two or more control modules.
Note that code U0401 is also sometimes further defined by a sub-code in this manner – U0401.XX. In these cases, the sub-code serves to define the particular system in which the fault is present. However, since not all manufacturers employ sub-codes, always refer to the manual for the affected application to determine the exact definition of code U0401 as it applies to that particular application.
In general terms though, all control modules on a modern application are interconnected via a highly complex web of wiring harnesses that is collectively known as the CAN (Controller Area Network) bus system. During normal vehicle operation, operational information and commands that affect all aspects of the vehicles’ operation are continually being exchanged between control modules, some of which are programmed to expect certain types of information from closely related modules.
In almost all cases, the PCM acts not only as a sort of clearing house for exchanged information, but it also “supervises” the exchange of information between control modules and should it detect a communication failure between two or more control modules for a period of time that exceeds a limit set by the manufacturer, it will set code U0401, and illuminate a warning light.
Where is the U0401 sensor located?
Due to the highly complex nature of modern CAN bus systems the fault can be located almost anywhere in the CAN bus system. However, in cases where there is no sub-code present, the fault is likely to involve wiring issues between the PCM and TCM (Transmission control Module), the PCM and the ABS control module, or the BCM (Body Control Module) and the airbags/seat belt control system.
However, depending on the application, other systems may be involved or implicated, so always refer to the manual for the application for details on the most likely fault locations, or the location of control modules that may have failed.
What are the common causes of code U0401?
Some common causes of code U0401 could include the following-
- Damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors
- Abnormal system voltages
- On some applications, defective engine and driveability sensors can cause this code, or contribute to its setting. Note however that in these cases, defective sensors will be indicated by dedicated codes
- One or more defective control modules. Note that control module failure is rare, and the fault must be sought elsewhere before any control module is replaced
What are the symptoms of code U0401?
Although the most symptoms of code U0410 are largely make and model specific, some common symptoms could include the following-
- Varying degrees of power loss may be present
- Misfire-like symptoms may be present on some applications
- Transmission may enter a fail-safe or limp mode
- The ABS or other safety systems such as Traction Control and/ or Stability Control may be deactivated or unavailable
NOTE: Refer to the manual for the affected application for detailed information on the symptoms that are most likely to be present on that application.
What are common solutions to code U0401?
Common solutions could include the following-
- Replacement of sections of wiring
- Replacement of individual wiring harnesses
- Replacement of failed or failing control modules
NOTE: Replacing control modules may sometimes require reprogramming of the replacement module, or integration of the replacement module into the CAN bus system to allow the PCM to recognize the replacement module. Failure to perform the reprogramming or integration process may result in a recurrence of the problem, or an inability to clear the code.
How serious is code U0401?
Code U0401should be considered as serious since in some cases, the vehicle could enter a fail-safe or limp mode.
How safe is it to still drive the car with code U0401?
The presence of code U0401 could affect the safe operation of the vehicle, and especially if the ABS/Traction Control/Stability Control systems are affected.
How difficult is it to repair code U0401?
It is sometimes possible to diagnose and repair code U0401 on a DIY basis; however, in most cases, diagnosing code U0401 requires the use of advanced, make-and-model specific diagnostic equipment, as well as above average diagnostic skills. Note that cheap, generic code readers are generally not able to diagnose CAN bus, or control module related codes. If suitable diagnostic equipment is not available, refer the vehicle to the dealer or other specialist repair facility for professional diagnosis and repair.
NOTE: Non-professional mechanics should take note that if the cause of this code is not obvious, such as a disconnected ground strap or obviously burnt/damaged wiring, the better option is to refer the vehicle to the dealer or other specialist repair facility for professional diagnosis and repair.
What are the common mistakes when repairing code U0401?
Control modules that could include the PCM/TCM are often condemned and replaced out of hand when the most likely causes of this code are wiring issues or poor electrical connections.
One other common mistake many mechanics make is not investigating and resolving codes that accompany U0401. For instance, codes that indicate low system voltages are often ignored, even though these codes are often the direct cause of U0401.
How do you troubleshoot code U0401?
WARNING: The information provided in this section s intended for general informational purposes only, and should NOT be used in ANY diagnostic/repair procedure on ANY application without making proper reference to the manual for the affected application. Failure to make proper reference to the manual WILL lead to misdiagnoses, wasted time, and the unnecessary replacement of expensive parts and components that could include control modules.
Record all fault codes present, as well as all available freeze frame data. This information could be of use should an intermittent fault be diagnosed later on.
NOTE: If other codes are present, make a careful note of the order in which they were stored, since resolving codes that precede U0401 in this order will sometimes resolve U0401 as well. Nonetheless, do NOT make an attempt to diagnose U0401before referring to the manual to determine which system(s) are affected by code U0401.
Once the affected system(s) is identified, perform a thorough visual inspection of all associated wiring. Look for damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors. Make repairs or replace wiring as required.
NOTE: Ground straps and other wiring is often left disconnected after routine maintenance or repairs. Make sure that all ground straps and electrical connectors are connected/fully engaged before proceeding to Step 3.
If no visible damage is found, perform resistance, ground integrity, continuity, and reference voltage (where applicable) on all associated wiring, but be sure to follow the directions in the manual exactly to ensure the most accurate and reliable test results.
NOTE: Disconnect all wiring from all implicated control modules during this step to avoid damaging one or more control modules.
Compare all obtained readings with the values stated in the manual and make repairs or replace wiring/connectors as required to ensure that all electrical values fall within the ranges specified by the manufacturer.
Clear all codes after repairs are complete, and operate the vehicle for at least one complete drive cycle to see if any codes return.
If the fault persists but all electrical values/circuits check out, suspect a defective control module or control switch.
Note though that from this point on, testing and diagnostic procedures become entirely make and model specific that can vary from removing the complete wiring harness from the vehicle for detailed inspection or replacement, to replacing suspect control modules with known good units to verify the existence of a fault in various parts of the CAN bus system.
Thus, if a defective control module is suspected, and professional grade diagnostic equipment and reference data is not available, the better option is to refer the vehicle to the dealer or other competent repair facility for professional diagnosis and repair.
Codes Related to U0401
There are no known codes that are directly related to U0401 – “Invalid data received – engine control module (ECM)
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hi I have a problem with my BT50 . received invalid data from ECM/PCM A
Any help how to fix it? please
I have a code U0401-68
Ich hab diese Fehler bei mein Auto
Invalid Data Received from ECM/PCM (Powertrain
Control Module) A
Gemischanpassung (Reihe 1)
Das Auto fährt ganz normal innen Stadt aber wenn ich auf der Autobahn fahren mehr als 100-200 Kilometer bei Geschwindigkeit 130-180kmh
Bekomme ich Getriebe Störung obwohl das Auto hat schon neu Inspektion gekriegt
Ich brauche eure Hilfe bitte 🥺
The car drives quite normally in the city but when I drive on the highway more than 100-200 kilometers at a speed of 130-180kmh
Do I get a gearbox fault even though the car has already had a new inspection
I need your help please
Did u get assistance with the U0401:00 6C fault ? We are experiencing the same issue and cannot find the problem .
Anas, it appears you have some wiring issues and this is affecting the CAN bus communication between the PCM and the TCM. Other than basic CAN bus voltage testing at the datalink connector (pins 6 and 14; each pin should have about 2.5 volts present) there’s nothing to check. You could look at the connections at both the PCM and TCM to see if there were any abnormalities (bad connectors, green contamination, etc). After that, a good diagnostician would be able to make needed repairs.
Ford ranger 2015 2. 2 manual in limp mode raves not going above 3000rpm.scanned and got error code U0401:00 tried looking for any shortened wire or harness without any luck. Help please
Hello I have u0401 code along with p0113 u0077 u0077 & c0800 the car is crank starting, any help on what to do
I just got my truck out of the shop after defective fuel filters caused a low fuel pressure fault.
Now I have the check engine light on and I get the following fault codes: P-1464 (PCM) and U-0401 (IPSM/ECM). Last year in Nov they had to replace the low pressure fuel pump after a low fuel pressure warning popped up. The other thing that has happened is that I can no longer scroll through the vehicle menu to check the DEF fluid level like I’ve been able to in the past.
I’m using the Forscan app to connect to the OBDII port and read the codes.
And the dealer can’t get me back in the shop until next thursday.
Any help will be greatly appreciated.
Hello Vincent. This code likely came on while they were testing your low fuel pressure. The p1464 has to do with the AC cycling clutch. Leaving it on or the defroster on while the mechanics have a scan tool connected doing what ford calls a KOEO self test. Which stands for key on, engine off. WILL set this code. Same with the U0401 code. Simply ask the mechanics to erase the code next time they are looking at your diesel. As for the U0401 code, I would look in your engine bay. There could be a main groundstrap maybe someone forgot to hook back up while servicing your vehicle. Hope this helps on your journey.
My car When starting and turning on the car, the anti-slip light on the odometer turns on. Please help
I am receiving this error code U0401-81, on a Tata Nexon. The company engineers here have done all of the above troubleshooting and finally also changed the ABS control module, still receive the ABS error, what needs to be done to rectify this issue
Is this the only DTC you’re getting? Also, which controller is putting out this DTC? The ECM and ABS controllers need to be scanned separately, most-likely needing a Tata scantool for the ABS. Has this car ever been in a crash? Seems odd to have a CAN BUS error in such a new vehicle.
Benjamin thanks for your reply,
Apologize for responding late as I was hospitalised.
Yes this is the only DTC code I receive,
This is a new car and has not been in a crash, Tata Motors uses their own company scantool. Since the vehicle is under warranty I take it to the Tata service centre only. the ABS issue happens intermittently…… It’s been more that 8 times now on this new car, after erasing the error from memory they first replaced the break switch, ABS/ ECM can wiring was found OK, ABS sensors resistance found OK, sensors cleaned n refit the next time they adjusted the break supply point and the last time they changed the ABS control module and still the error show up, any other troubleshooting steps that can be taken to resolve the issue.
Ouch, sorry to hear that. Regarding the car, it’s odd that there’s such a problem on a new car. Maybe Tata needs to get a specialist on it or buy it back. New car shouldn’t have problems like that, but it happens.
Thanks for your reply Benjamin,
Now the guys from TATA are telling me this is not an error, this is a feature given for safety. He mentioned this happens when the brake pedal is pressed lightly (exactly 15% pressure applied) for 60secs continuously ( while driving or car is idling) the ABS light will show up on cluster. After so much troubleshooting and changing so many parts they now say it’s a feature. Found this explanation very weird. How can this be possible?
HOLA VEO QUE ES UN AÑO ATRÁS ESTE CASO PERO SI SIRVE DE ALGO PARA FUTUROS LECTORES LES CUENTO QUE SI ES POSIBLE QUE QUE EL MODO DE CONDUCCIÓN AFECTE SIGNIFICATIVAMENTE EL FUNCIONAMIENTO DEL VEHÍCULO ESTO ESTE CODIGO COMO BIEN SABEN ES GENÉRICO, PARA LA MAYORÍA DE LAS MARCAS EXISTEN DIVERSAS PROGRAMACIONES DE LA ECM Y PCM ASÍ COMO PARA OTROS MÓDULOS COMO EL DEL ABS INCLUSO DE CARROCERÍA ….LO QUE QUE QUIERO DECIR EN TÉRMINOS CRIOLLOS ES QUE LOS MÓDULOS O COMPUTADORAS ESTÁN PROGRAMADOS SEGÚN CADA FABRICANTE BIEN SEA EN ESTE CASO PARA CUANDO CONDUCES CON EL PIES LIGERAMENTE (15 % ) SOBRE EL PEDAL DEL FRENO Y A SU VEZ ESTAS ACELERANDO, LA COMPUTADORA O MODULO NO PROCESA LA SEÑAL QUE RECIBE (PORQUE NO ESTA PROGRAMADA PARA ESTE TIPO DE MALA CONDUCCIÓN ) Y SE PONE EN MODO DE EMERGENCIA ….SE DISPARA UN ALERTA POR SEGURIDAD SE ENCIENDE LA LUZ DE SERVICIO , PERO COMO EN REALIDAD EL VEHÍCULO NO FALLA Y SI FALLA ES ALGO INTERMITENTE POR QUE SE TRATA DE UN ERROR HUMANO AL CONDUCIR , ESTE SE VA IR INCREMENTANDO A MEDIDA QUE CONDUCES EL VEHÍCULO Y ASÍ LE CAMBIES TODO EL RAMAL FUSIBLES MÓDULOS Y COMPUTADORAS SIGUES COMETIENDO EL MISMO ERROR DE CONDUCCIÓN Y MAS SI EL VEHÍCULO ESTA NUEVO QUE ESTA SENSIBLE AL MÍNIMO TOQUE O PRESIÓN QUE PUEDAS ESTAR EJERCIENDO SOBRE EL PEDAL DEL FRENO DE MANERA INCONSCIENTE Y SUPONIENDO QUE CORRIJAS LA MANERA DE CONDUCIR ES POSIBLE QUE EL SENSOR DEL PEDAL DEL FRENO YA ESTE TAMBIÉN AFECTADO Y CREO DESGASTE POR LO TANTO TAMBIÉN HAY QUE CAMBIARLO ….ESPERO LES SIRVA ESTA INFORMACIÓN QUE ME HA SERVIDO DE MUCHO PARA MUCHOS DE MIS CLIENTES QUE COMETEN ESTE ERROR Y ESO DEPENDE TAMBIÉN DE LO NUEVO DEL VEHÍCULO Y DEL TIPO DE PROGRAMACIÓN DE FABRICA INCLUSO SI CAMBIASTE DE VEHÍCULO Y TIENE OTRO CONFORT LA POSICIÓN DEL ASIENTO HACE QUE CAMBIES INCONSCIENTEMENTE EL MODO DE CONDUCCIÓN
What’s the purpose of the ABS light, then? I mean, what possible function could that have? I’d love to hear the explanation. (This has nothing to do with DTC U0401, though, does it?)
First of all check the alternator it should bring out voltage above 13 to 14 volts but not less than 13 then you have a problem .and it also check s out with that code
Hi I have problem with my car Jaguar XF 2011. Received in valid data from ECM/PCM U0401-08