P174F: Fuel Trim Cylinder Balance Bank 2
8 vehicles · 2 makes · $300-$8,000 repair
Most Reported On
P174F is an OBD-II diagnostic trouble code meaning “Fuel Trim Cylinder Balance Bank 2.” This is a manufacturer-specific fuel-system code (used by some makes, notably BMW) indicating a fuel trim cylinder balance problem on Bank 2 — the bank of cylinders that does not contain cylinder 1. The engine computer compares how much fuel correction each cylinder needs and sets this code when one or more cylinders on Bank 2 run noticeably richer or leaner than the others, creating an air/fuel imbalance. It generally points to something disturbing fueling or air on individual cylinders rather than the whole bank. Symptoms can include rough idle, slight misfire feel, and reduced smoothness. This code is most commonly reported on 2008-2017 Audi A5 (Premium, Premium Plus, Prestige), 2009-2020 Audi A4, and 2008-2024 Audi R8, plus 5 other vehicles, with repair costs ranging from $300 to $8,000.
Common Causes
Typical Repair Cost
Based on 9 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P174F, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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Vehicles Affected (8)
S-Tronic/DSG Mechatronic Unit Failure
S-Tronic (DSG) Mechatronic Unit Issues
S-tronic Transmission Actuator Failure
DQ250 DSG Mechatronic Unit Failure
DSG Transmission Issues (7-Speed DQ500)
DQ381 S-Tronic Mechatronic Unit Failure
Transmission Mechatronic Unit Failure (8-Speed Tiptronic)
DQ381/DQ250 S tronic Mechatronic or Internal Transmission Fault Causing No-Drive, Jerking, or Gearbox Warning
FAQ
What does P174F mean?
P174F stands for "Fuel Trim Cylinder Balance Bank 2." This is a manufacturer-specific fuel-system code (used by some makes, notably BMW) indicating a fuel trim cylinder balance problem on Bank 2 — the bank of cylinders that does not contain cylinder 1. The engine computer compares how much fuel correction each cylinder needs and sets this code when one or more cylinders on Bank 2 run noticeably richer or leaner than the others, creating an air/fuel imbalance. It generally points to something disturbing fueling or air on individual cylinders rather than the whole bank. Symptoms can include rough idle, slight misfire feel, and reduced smoothness.
What are the most common causes of P174F?
The most common causes of P174F are: Dirty, clogged, or leaking fuel injector on a Bank 2 cylinder, Intake or vacuum leak affecting individual cylinders, Weak or fouled spark plug / ignition coil causing imbalance, Low or uneven fuel pressure, Faulty oxygen/air-fuel sensor on Bank 2, Carbon buildup on intake valves (direct-injection engines), Compression or valve issue on a Bank 2 cylinder. The specific cause varies by vehicle.
How much does it cost to fix P174F?
Repair costs for P174F range from $300 to $8,000, depending on the vehicle and root cause.
Which vehicles are affected by P174F?
Au7o has documented P174F across 8 vehicle models from 2 manufacturers: Audi, Skoda.
Sources (6)
- NHTSANHTSA Complaint #10629867 - 2010 Audi A4 transmission failure / gearbox malfunction
- ForumAudi RS3 Owners Club / AudiRS3.org - DQ500 DSG service and failure reports thread
- videoAudi S3 DQ381 Mechatronic Unit Replacement - B is for Build
- RecallNHTSA Recall 24V-213 / Audi transmission defect may cause loss of drive power (certain 2022-2024 A3/S3)
- NHTSANHTSA complaints database - Audi A3 transmission complaints
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.