U0100 on FORD FOCUS — Lost Communication With ECM/PCM A

Q: "What does U0100 mean on a FORD FOCUS?"

"U0100 indicates: Lost Communication With ECM/PCM A. This is a network communication code. 3 FORD FOCUS owners have reported this to NHTSA."

Q: "What are the most common causes of U0100 on FORD FOCUS?"

"Based on 3 NHTSA reports, the most commonly cited components are: Power Train, Power Train,Engine, Electrical System,Unknown Or Other. These percentages are based on the component field in owner complaints."

Q: "Is U0100 serious on my FORD FOCUS?"

"Of 3 NHTSA reports for this code on FORD FOCUS, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic."

Q: "What should I do if my FORD FOCUS shows U0100?"

"1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare."

What U0100 Means on Your FORD FOCUS

U0100 is a diagnostic trouble code indicating: Lost Communication With ECM/PCM A. This code relates to the network communication system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

3 FORD FOCUS owners have reported this issue to NHTSA across model years 2012-2014. Most reports come from the 2014, 2012 model years.

Real FORD FOCUS Owner Reports

Source: NHTSA Complaints Database

"*ongoing *please see original complaint # 10473215 *clutch replaced twice and trans reprogrammed 4/5 times (within 35, 000) *now car not starting- 4 times in 2 months."

— 2012 FORD FOCUS owner · POWER TRAIN · Filed 01/03/2015

"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."

— 2014 FORD FOCUS owner · POWER TRAIN,ENGINE · Filed 04/12/2022

"Some 2011-2016 fiesta and 2012-2016 focus vehicles equipped with a dps6 transmission may exhibit intermittent concerns of loss of transmission engagement while driving, intermittent no syart or loss of power. these symptoms are usually accompanied by an illuminated check engine lamp."

— 2014 FORD FOCUS owner · ELECTRICAL SYSTEM,UNKNOWN OR OTHER · Filed 06/17/2018

All reports filed by vehicle owners directly with the U.S. Department of Transportation.

📊 Complaint Trend by Model Year

1

'12

2

'14

Common Causes on FORD FOCUS

Based on NHTSA complaint component analysis for this vehicle.

POWER TRAIN 33.3%

POWER TRAIN,ENGINE 33.3%

ELECTRICAL SYSTEM,UNKNOWN or OTHER 33.3%

What To Do Next

1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.

Frequently Asked Questions

What does U0100 mean on a FORD FOCUS? ▾

U0100 indicates: Lost Communication With ECM/PCM A. This is a network communication code. 3 FORD FOCUS owners have reported this to NHTSA.

What are the most common causes of U0100 on FORD FOCUS? ▾

Based on 3 NHTSA reports, the most commonly cited components are: Power Train, Power Train,Engine, Electrical System,Unknown Or Other. These percentages are based on the component field in owner complaints.

Is U0100 serious on my FORD FOCUS? ▾

Of 3 NHTSA reports for this code on FORD FOCUS, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my FORD FOCUS shows U0100? ▾

1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare.