P1085 Code - Fuel Control Mixture Lean Bank 2 Sensor 1
Quick Answer
To operate effectively, a gasoline engine requires a specific air-fuel ratio (lambda), with the theoretical ratio being 14.7:1. Common causes include Faulty Crankcase Ventilation Control Valve, Damage or loose Air Intake Tube, Faulty Mass Air Flow (MAF) sensor. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1085 indicates Fuel Control Mixture Lean Bank 2 Sensor 1.
- Common causes
- Common causes include Faulty Crankcase Ventilation Control Valve, Damage or loose Air Intake Tube, Faulty Mass Air Flow (MAF) sensor.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P1085 Description
For maximum power output, a rich mixture is necessary during full-throttle operation. If lambda is less than 1, there is insufficient air, and the fuel-air mixture becomes rich. On the other hand, if lambda is greater than 1, there is excess air, and the mixture becomes lean, reducing fuel consumption and power output.
However, if lambda exceeds 1.3, the air-fuel mixture becomes difficult to ignite, and the engine no longer operates within safe limits. In practical applications, a lambda value of 0.9 to 1.1 has proven to be most favorable. If the engine needs to operate at a lambda value of 1, a fuel injection system with emission control will be necessary to ensure proper mixture preparation.
The electronic fuel injection system measures the engine's air intake and converts it into an electrical signal for evaluation by the DME control unit. Based on this signal and other parameters, the control unit calculates the fuel requirement and activates electromagnetic fuel injectors. These injectors intermittently inject fuel ahead of the cylinder inlet valves.
What are the Possible Causes of the DTC P1085?
- Faulty Crankcase Ventilation Control Valve
- Damage or loose Air Intake Tube
- Faulty Mass Air Flow (MAF) sensor
- Faulty Ignition Coil(s)
- Faulty Spark Plugs
- Insufficient fuel pressure
- Large vacuum leak on the engine
How to Fix the DTC P1085?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1085 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P1085 code?
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Need Help with the Code?
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Information for Specific Makes
- P1085 Audi — Exhaust Bank 4- Mixture Adaption Range 1 Lower Lean Limit Not Reached
- P1085 BMW — Fuel Control Mixture Lean Bank 2 Sensor 1
- P1085 Isuzu — High Pressure Fuel Pump Performance
- P1085 MINI — Fuel Control Mixture Lean Bank 2 Sensor 1
- P1085 Volkswagen — Exhaust Bank 4- Mixture Adaption Range 1 Lower Lean Limit Not Reached
Frequently Asked Questions about P1085 Code
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