U0401: Invalid Data Received From ECM/PCM A
What Does U0401 Mean?
U0401 is a diagnostic trouble code indicating: Invalid Data Received From ECM/PCM A. This code relates to the network communication system. It has been reported in NHTSA complaints across 19 different vehicle models.
Symptoms of U0401
- ⚠️ Check engine light illuminated
- ⚠️ Engine misfires
- ⚠️ Loss of engine power
- ⚠️ Knocking or pinging noise
- ⚠️ Traction control system activated
- ⚠️ Vehicle enters limp/reduced power mode
Common Causes
- 🔍 Worn or fouled spark plugs
- 🔍 Failed ignition coil
- 🔍 Throttle body or throttle position sensor issue
- 🔍 Stuck or failed EGR valve
- 🔍 Wiring or connector problem
- 🔍 Sensor or control module malfunction
U0401 Reports by Year
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"The issue first appeared during my initial test drive before purchase in 2019. The salesman stated it was a low-battery issue from the car sitting on the lot. Since then, the same problem has recurred multiple times. The vehicle displays multiple warning lights — “Electric Powertrain Fault,” Check "
— Honda Accord owner, 06/21/2019
"Began getting several alerts, when taken in to get a diagnosis I received the following error codes P0301, P0304, P0301, P0300, U0401-68 & U3003-16. These codes stated that I had Cylinder 1 Misfire, Cylinder 4 Misfire as well as Random Misfire and ECM Failure and Electric Parking Brake Control Unit "
— Honda Accord owner, 12/04/2023
"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 VS"
— Honda Accord owner, 05/02/2022
Source: NHTSA Complaints Database
Most Reported Vehicles for U0401
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | HONDA ACCORD | |
| 2 | JEEP COMPASS | |
| 3 | HONDA CR-V | |
| 4 | FORD FOCUS | |
| 5 | CHEVROLET MALIBU | |
| 6 | JEEP PATRIOT | |
| 7 | CHRYSLER 200 | |
| 8 | HONDA PILOT | |
| 9 | HONDA FIT | |
| 10 | HONDA HR-V | |
| 11 | HONDA INSIGHT | |
| 12 | FORD FUSION | |
| 13 | CHEVROLET COLORADO | |
| 14 | DODGE DURANGO | |
| 15 | DODGE DART |
U0401 Reports by Vehicle
Detailed NHTSA complaint analysis for each vehicle model.
Diagnostic Tips
- Scan all modules, save freeze-frame data, and clear unrelated history codes before focusing on U0401.
- Confirm whether companion codes are present first; they often identify the root cause sooner than the headline DTC.
- Prioritize inspection around power train and the most common failure path for this code family.
- Perform a voltage-drop and continuity check on the affected circuit and verify 5V reference/ground stability under load.
- After each repair step, complete one drive cycle and verify readiness monitors instead of judging success after a quick idle test.
- If the code keeps returning on high-incidence platforms (for example HONDA ACCORD), check TSB patterns and wiring/connector fitment before major part replacement.
Common Mistakes to Avoid
- ❌ Skipping freeze-frame review and losing the exact RPM/load conditions when the fault set.
- ❌ Replacing modules before checking grounds, voltage drop, and harness rub-through near heat/vibration points.
- ❌ Clearing U0401 and returning the car before monitors complete — this often creates repeat visits.
- ❌ Treating intermittent wiring or connector faults as permanent component failure without wiggle testing.
Frequently Asked Questions
Can I drive with this code?
Will this code clear itself?
How do I find the exact cause?
What To Do Next
Possible Fixes
- 🔧 Have the code scanned with a professional-grade scanner to read freeze frame data
- 🔧 Test the relevant sensor(s) with a multimeter before replacing
- 🔧 Inspect wiring harness and connectors for damage, corrosion, or loose connections
- 🔧 If DIY repair isn't feasible, get a diagnostic from a trusted mechanic ($50-150)
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.