P2187 on 2010-2017 Audi S5 (Premium Plus, Prestige) — System Too Lean at Idle (Bank 1)
1 vehicles · 1 makes · $600-$1,200 repair
Most Reported On
P2187 is an OBD-II diagnostic trouble code meaning “System Too Lean at Idle (Bank 1).” This code means the engine's computer has detected the air-fuel mixture on Bank 1 is too lean specifically at idle, while it stays acceptable at higher speeds. The computer monitors the oxygen sensors and has had to add significant fuel correction at idle to compensate. Because the fault appears mainly at idle, it usually points to a small vacuum or air leak that has a big effect when airflow is low. Symptoms often include rough or unstable idle, stalling, and hesitation when first taking off. This code is most commonly reported on 2010-2017 Audi S5 (Premium Plus, Prestige), with repair costs ranging from $600 to $1,200.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P2187, 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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FAQ
What does P2187 mean?
P2187 stands for "System Too Lean at Idle (Bank 1)." This code means the engine's computer has detected the air-fuel mixture on Bank 1 is too lean specifically at idle, while it stays acceptable at higher speeds. The computer monitors the oxygen sensors and has had to add significant fuel correction at idle to compensate. Because the fault appears mainly at idle, it usually points to a small vacuum or air leak that has a big effect when airflow is low. Symptoms often include rough or unstable idle, stalling, and hesitation when first taking off.
What are the most common causes of P2187?
The most common causes of P2187 are: Small vacuum leak (hose, gasket, or fitting), Intake manifold or throttle body gasket leak, Faulty or leaking PCV valve/hose, Dirty or failing mass airflow (MAF) sensor, Leaking or dirty fuel injectors, Faulty upstream oxygen sensor, Low fuel pressure at idle, Leaking brake booster or its vacuum hose. The specific cause varies by vehicle.
How much does it cost to fix P2187?
Repair costs for P2187 range from $600 to $1,200, depending on the vehicle and root cause.
Which vehicles are affected by P2187?
Au7o has documented P2187 across 1 vehicle models from 1 manufacturers: Audi.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.