U0401: Invalid Data Received From ECM/PCM A
A generic network and communication trouble code, same meaning on every brand.
Yes with care - behavior depends on which module distrusts the engine data.
Symptoms
- Multiple warning lights
- Harsh shifting
- Traction control disabled
- Symptoms that seem unrelated to each other
Likely causes, most common first
- Engine computer sending implausible data - often a failing sensor upstream
- Software mismatch after a module replacement
- Bus interference
- Failing engine computer
Read U0401 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
U0401 is subtly different from the lost-communication codes around it: the engine computer is talking, but another module considers what it says invalid. It is a complaint about content, not silence.
That usually makes it a symptom rather than a disease. A failing sensor feeds the engine computer garbage, the computer relays it, and the transmission or ABS module files this complaint about the relay. The productive move is reading codes from every module and fixing the engine-side faults first - U0401 routinely clears itself once the upstream sensor that started the chain is repaired. It appearing right after a module was replaced or reflashed points instead at mismatched software versions.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning U0401
“While driving, error popped up stating steering assist is reduced; drive with caution. Heat was no longer working. Engine temp was reading cold even though vehicle had been running for half hour and temp outside was 65 F. After vehicle was stopped, engine fan ran very loudly for at least 15 minutes. Took vehicle in to have diagnostics ran, and received error P0128 pointing to faulty engine coolant thermostat and sensor. Also received U0401 indicating insufficient data coming from ECM/PCM. I was told that together with U0401 and P0128 together indicate a communication problem between control modules. Check engine light was never on.”2021 GMC Acadia · Oct 2025
“1) power train system- P090C AND P090C-00 clutch b actuator circuit low causing transmission to slip. dangerous when driving 2) anti-lock brake system code U0401-00 and U3003-16”2014 Ford Focus · Jul 2025
“Connecting rod bearing Failure. stalled in traffic. Waring lights included. emissions system problem VSA Problem Hill Start Assist Problem Trailer Stability Assist Problem Road Departure System Problem Emissions System Problem Power Steering System Problem All Wheel Drive (AWD) System Problem. also getting DTC Coded P0303_Cylinder 3 Misfire U0401-68_ECM Failure F-Can Time Out_ EAT_40F (NG) Loud Knocking coming from engine while running. removed the oil pan and rod bearing. Found Metal Shavings in the oil pan. located the loose connecting rod and removed the bearing.”2016 Honda Pilot · Nov 2023
Show 7 more owner reports
“Truck completely lost power while driving on the highway 4 times and 4 other times during morning commute through busy streets. Dangerous circumstance to be put in while driving. Codes given at Auto Zone: P2112 U3013-16 U0401-02 U0401-00 U0131-00 U0151-00 U0100-00”2016 Ford F-150 · May 2023
“Have a hard brake pedal. U0401 code. Ford replaced battery. It got rid of code but still had a hard brake pedal. Ford replaced power assist unit. That fix the problem.”2013 Lincoln MKX · Nov 2022
“CMS - collision mitigation system stops working completely. 2 warning lamps on dash. Cruise control completely inoperative. Vehicle was initially inspected by dealer on 11/19/21with DTC U0401-92 - Temporary stop of integrated driver support system (rejected control request), also found U0416-68 VSA system malfunction. This issue happens every 1-3 thousand miles. Also with the CMS/braking system, it will alert "brake" on dash and brake hard if encountering repetitive shadows from objects that are cast onto the road. My safety and others safety were compromised due to hard braking and cars behind me that then had to brake, nearly rear-ending my car.”2020 Honda Accord · May 2022
“The contact owns a 2014 Ford Focus. The contact stated that on numerous occasions while shifted into reverse(R), the vehicle failed to respond. The contact also stated that while shifted into reverse(R), the RPM increased and the engine revved while the brake pedal was depressed. No warning light was illuminated. The vehicle was taken to an AutoZone where it was placed on a diagnostic machine and produced codes: P090C, U0100-00, U3003-17, U3003-16, U0101-00, U0401-00. The vehicle was taken to the dealer where the failure could not be duplicated. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 114,000.”2014 Ford Focus · Apr 2022 · 114,000 mi
“Shift indicator light will flash and go off. Check engine light and wrench light comes on for coded P0706, P0707, P1702, P1921. U0401. Needed range sensor. Shifted when it wanted to and quit altogether then start back up. Had range sensor replaced.”2017 Ford F-150 · Dec 2021
“Traveling 40 mph engine misfires check engine, throttle body, and traction warning lights on. Vehicle will not accelerate. Turn off engine resets throttle body and traction control warning lights check engine light remains on vehicle accelerates normally. Check engine code = u0401 invalid data received from engine control module/powertrain control module a. 84,000 miles”2014 Jeep Patriot · Jan 2020 · 84,000 mi
“Vehicle abruptly slowed in heavy traffic for no apparent reason. Vehicle was diagnosed as having a faulty accelerator pedal. Part was replaced at owners expense 14 months into the life of the car. 8 months later the vehicle started to do the same thing for the next 5 months, sometimes 3 to 4 times in one day or not al all for several weeks. Car was again presented to dealer for diagnostic and it showed that the same fault occurred. This is a severe safety issue that needs to be addressed by general motors. Fault codes p2138 for accelerator pedal, c0242 and u0401 for traction control system. Neither of these faults were addressed by the dealer during the repair.”2017 Chevrolet Malibu · Nov 2019
Cars that report U0401 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with U0401?
Yes with care - behavior depends on which module distrusts the engine data.
How much does it cost to fix U0401?
Typical US repair costs range from $100 for the simplest fix (upstream sensor diagnosis and repair) to $1,500 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to U0401. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.