P1085 on 2000-2003 BMW M5 — Fuel Control Mixture Lean, Bank 2 Sensor 1 (manufacturer-specific, common on BMW)
1 vehicles · 1 makes · $300-$900 repair
Most Reported On
P1085 is an OBD-II diagnostic trouble code meaning “Fuel Control Mixture Lean, Bank 2 Sensor 1 (manufacturer-specific, common on BMW).” P1085 is a manufacturer-specific powertrain code, most commonly seen on BMW, indicating a lean fuel/air mixture on bank 2 of the engine as detected by the upstream oxygen sensor. The computer detected it was adding excessive fuel to correct for too much unmetered air, signaling a lean condition. It very commonly sets together with P1083 (the bank 1 equivalent), which usually points to an air leak affecting the whole engine rather than just one bank. This code is most commonly reported on 2000-2003 BMW M5, with repair costs ranging from $300 to $900.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P1085, 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 P1085 mean?
P1085 stands for "Fuel Control Mixture Lean, Bank 2 Sensor 1 (manufacturer-specific, common on BMW)." P1085 is a manufacturer-specific powertrain code, most commonly seen on BMW, indicating a lean fuel/air mixture on bank 2 of the engine as detected by the upstream oxygen sensor. The computer detected it was adding excessive fuel to correct for too much unmetered air, signaling a lean condition. It very commonly sets together with P1083 (the bank 1 equivalent), which usually points to an air leak affecting the whole engine rather than just one bank.
What are the most common causes of P1085?
The most common causes of P1085 are: Vacuum or intake air leak after the MAF sensor, Failed crankcase ventilation (CCV) valve/hoses (BMW), Dirty or failing mass airflow (MAF) sensor, Cracked or loose intake boot and manifold gaskets, Weak fuel pump or restricted fuel injectors, Faulty upstream oxygen (O2) sensor on bank 2, Leaking PCV or oil-cap/dipstick seals. The specific cause varies by vehicle.
How much does it cost to fix P1085?
Repair costs for P1085 range from $300 to $900, depending on the vehicle and root cause.
Which vehicles are affected by P1085?
Au7o has documented P1085 across 1 vehicle models from 1 manufacturers: BMW.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.