P2578: Turbocharger/Supercharger Speed Sensor A Circuit
Methodology: Reviewed against the SAE J2012 generic DTC definition and NHTSA owner-complaint patterns, then scoped to generic code level because this page is not scoped to one make or model.
Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).
- SAE J2012 Diagnostic Trouble Code Definitions — Generic diagnostic trouble code definition reference for P2578.
- NHTSA recalls, complaints, and manufacturer communications — Used to check public owner complaint context, recall status, and safety-related manufacturer communications by VIN or vehicle.
Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.
What Does P2578 Mean?
P2578 code: Turbocharger/Supercharger Speed Sensor A Circuit. Symptoms, likely causes, diagnostic path, severity, and repair cost context.
Symptoms of P2578
- ⚠️ Warning light or diagnostic trouble code is stored
- ⚠️ Fuel economy may drop, fuel smell or exhaust smell may increase, or emissions readiness may fail
- ⚠️ The vehicle may drive normally while the monitor continues to fail
- ⚠️ Vehicle may fail an emissions or safety inspection until the code is resolved and monitors reset
Common Causes
- 🔍 Sensor reading, wiring, connector, actuator, emissions, or module condition detected by the control module
- 🔍 Low battery voltage, poor ground, software, or network issue affecting the related circuit
- 🔍 Mechanical condition that should be confirmed with live data before replacing parts
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"I was driving and all of a sudden could not go over 30 miles an hour. I took it 3 dealerships 1 including a Ford Dealership. What I have been told is that there have been many issues with this type/manufacturer of transmission. The diagnostic codes that are coming out when being run are P072C P2832"
— Ford Focus owner, 2022-08-04
Source: NHTSA Complaints Database
Most Reported Vehicles for P2578
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | FORD FOCUS |
Frequently Asked Questions
Is P2578 enough to replace a part?
Can I drive with P2578?
What To Do Next
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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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3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.