P1084 BMW – Rich Fuel Control Mixture, Bank 1 Sensor 1

P1084 BMW Possible Causes

  • Low fuel pressure
  • Large vacuum leak in the engine
  • Faulty Mass Air Flow (MAF) sensor
  • Faulty ignition
  • Faulty fuel injector

How to Fix BMW P1084 Code?

Start by checking the “possible causes” listed above. Visually inspect the wiring harness and corresponding connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Engine light on (or engine service warning light soon)

P1084 BMW Meaning

Fuel Control Mixture Rich Bank 1 Sensor 1 is the generic description for the P1084 BMW code, but the manufacturer may have a different description for your vehicle model and year. Currently, we do not have more information about the OBDII P1084 BMW code.

P1084 INFINITI – Exhaust Valve Timing Control Position Sensor Circuit, Bank 2

P1084 INFINITI Possible Causes

  • Faulty exhaust valve timing control position sensor, bank 2
  • Open or short circuit in exhaust valve timing control position sensor harness, bank 2
  • Poor electrical connection in exhaust valve timing control position sensor circuit
  • Debris accumulation in camshaft signal pickup portion
  • Crankshaft position sensor

How to Fix P1084 INFINITI Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

When is the Code Detected?

Excessively high or low sensor voltage is sent to the Engine Control Module (ECM).

Symptoms

Possible
Illuminated engine light (or service engine soon warning light)

P1084 INFINITI Meaning

The exhaust valve timing control position sensor detects the concave groove at the rear end of the exhaust camshaft.
This sensor signal is used to detect the position of the exhaust camshaft.
This sensor uses a Hall IC.
Based on the exhaust camshaft position, the ECM controls the exhaust valve timing control magnet retarder to optimize the exhaust valve closing/opening timing for driving conditions.

P1084 NISSAN – Exhaust Valve Timing Control Position Sensor Circuit, Bank 2

P1084 NISSAN Possible Causes

  • Faulty exhaust valve timing control position sensor, bank 2
  • Open or short circuit in the exhaust valve timing control position sensor harness, bank 2
  • Poor electrical connection in the exhaust valve timing control position sensor circuit
  • Debris accumulation in the camshaft signal pickup area
  • Crankshaft position sensor

How to Fix P1084 NISSAN Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

When is the Code Detected?

Excessively high or low sensor voltage is sent to the Engine Control Module (ECM).

Symptoms

Possible
Check Engine Light illuminated (or service engine soon warning light)

P1084 NISSAN Meaning

The exhaust valve timing control position sensor detects the concave groove at the rear end of the exhaust camshaft.
This sensor signal is used to detect the position of the exhaust camshaft.
This sensor uses a Hall IC.
Based on the exhaust camshaft position, the ECM controls the exhaust valve timing control magnet retarder to optimize the exhaust valve closing/opening timing for driving conditions.

P1085 – Fuel Trim Control Lean Mixture, Bank 2 Sensor 1

P1085 Possible Causes

  • Low fuel pressure
  • Large vacuum leak in the engine
  • Faulty mass air flow (MAF) sensor
  • Faulty ignition
  • Faulty fuel injector

How to Fix Code P1085?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Symptoms

Possible

Engine light on (or engine service warning light soon)

P1085 Meaning

Fuel mixture control lean bank 2 sensor 1 is the generic description for code P1085, but the manufacturer may have a different description for your vehicle model and year. Currently, we have no further information about OBDII code P1085.

P1085 AUDI – Exhaust Line 4 – Fuel Mixture 1 Adaptation Range Lower Lean Limit Not Reached

P1085 AUDI Possible Causes

  • Faulty oxygen sensor
  • Oxygen sensor harness open or shorted
  • Poor electrical connection in oxygen sensor circuit

How to Fix P1085 AUDI Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Check engine light illuminated (or service engine soon warning light)

P1085 AUDI Meaning

Exhaust Line 4 – Fuel Mixture Adaptation Range 1 Lower Lean Limit Not Reached is the generic description for Audi P1085 code, but the manufacturer may have a different description for your vehicle model and year. Currently, we don’t have more information about the Audi P1085 OBDII code.

P1085 BMW – Lean Fuel Mixture Control, Bank 2 Sensor 1

P1085 BMW Possible Causes

  • Low fuel pressure
  • Large vacuum leak in the engine
  • Faulty mass air flow (MAF) sensor
  • Faulty ignition
  • Faulty fuel injector

How to Fix BMW P1085 Code?

Start by checking the “possible causes” listed above. Visually inspect the wiring harness and corresponding connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Engine light on (or engine service warning light soon)

P1085 BMW Meaning

Fuel Control Mixture Lean Bank 2 Sensor 1 is the generic description for the P1085 BMW code, but the manufacturer may have a different description for your vehicle model and year. Currently, we do not have more information about the OBDII P1085 BMW code.

P1085 ISUZU – High Pressure Fuel Pump Performance

P1085 ISUZU Possible Causes

  • Faulty fuel pressure sensor
  • Fuel pressure sensor harness is open or short-circuited
  • Poor electrical connection in the fuel pressure sensor circuit
  • Fuel system leak
  • Faulty fuel injector

How to Fix P1085 ISUZU Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding cable harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Engine light on (or engine service warning light soon)

P1085 ISUZU Meaning

High-pressure fuel pump performance is the generic description for P1085 Isuzu code, but the manufacturer may have a different description for your vehicle model and year. Currently, we do not have additional information about OBDII code P1085 Isuzu.

P1085 VOLKSWAGEN – Exhaust Line 4 – Mixture Adaptation Range 1 Lower Lean Limit Not Reached

P1085 VOLKSWAGEN Possible Causes

  • Faulty oxygen sensor
  • Oxygen sensor harness is open or shorted
  • Poor electrical connection in the oxygen sensor circuit

How to Fix P1085 VOLKSWAGEN Code?

Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Check engine light on (or service engine soon warning light)

P1085 VOLKSWAGEN Meaning

Exhaust Line 4 – Fuel Mixture Adaptation Range 1 Lower Lean Limit Not Reached is the generic description for Volkswagen code P1085, but the manufacturer may have a different description for your specific vehicle model and year. Currently, we do not have more information about Volkswagen OBDII code P1085.

P1086 – Rich Fuel Control Mixture, Bank 2 Sensor 1

P1086 Possible Causes

  • Low fuel pressure
  • Large vacuum leak in the engine
  • Faulty Mass Air Flow (MAF) sensor
  • Faulty ignition
  • Faulty fuel injector

How is P1086 Code Repair Done?

Start by checking the “Possible Causes” listed above. Visually inspect the wiring harness and corresponding connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Check engine light on (or service engine soon warning light)

P1086 Meaning

Fuel Control Mixture Rich Bank 2 Sensor 1 is the generic description for code P1086, but the manufacturer may have a different description for your vehicle model and year. Currently, we have no further information about OBDII code P1086.

P1086 AUDI – Exhaust Bank 4 – Fuel Mixture Adaptation Range 2 Lower Lean Limit Not Reached

Severity of Code P1086 (Audi)

Level: Medium to High 🟠

  • Immediate impact:
  • Compromised air-fuel mixture regulation (risk of excessive consumption or reduced performance).
  • Increased pollutant emissions (exceeding EURO standards).
  • Long-term risks:
  • Catalyst damage (high cost: €800 to €2,500).
  • Clogged injectors or valves if the mixture is too rich.
  • The vehicle may activate a limp mode (power limitation on some TFSI/TDI models).

Common Symptoms of P1086

  • 🚨 Check Engine Light (MIL) on or flashing.
  • 📉 Increased fuel consumption (up to 15%).
  • 🛑 Unstable idle or abnormal vibrations.
  • ⚠️ Failed emissions test (due to non-compliant emissions).
  • 🌫️ Sulfur smell from the exhaust (mixture too rich).

Main Causes of P1086 (Audi)

  1. Lambda sensor failure (Bank 2, Sensor 2):
  • Normal wear, contamination from combustion residues or silicones (e.g., unsuitable sealants).
  1. Electrical issues:
  • Cut wires or short circuit in the sensor harness (e.g., thermal damage near the catalyst).
  • Oxidized connectors (moisture, winter salt) or bent pins.
  1. Exhaust leaks:
  • Cracked exhaust manifold gasket or loose clamp (false sensor reading).
  1. Air-fuel mixture problems:
  • Clogged injectors, faulty MAF sensor, or intake system leak.
  1. PCM failure:
  • Software calibration error (requires an Audi SSP update).

Detailed Diagnostic Procedure

Required Tools

  • Audi-compatible OBD2 scanner (e.g., VCDS, ODIS).
  • Digital multimeter (resistance/voltage testing).
  • Elsawin or Erwin documentation for wiring diagrams.

Key Steps

  1. Reading codes and live data:
  • Use VCDS to:
    • Check related codes (e.g., P0171, P2096).
    • Analyze Bank 2, Sensor 2 values (voltage in mV, response time).
    • Compare with Bank 1, Sensor 2 to identify discrepancies.
  1. Visual inspection:
  • Examine the sensor harness (e.g., sections exposed to heat near the catalyst).
  • Look for exhaust leaks before the sensor (use a smoke machine if necessary).
  1. Electrical sensor test:
  • Measure the heater resistance (Audi specifications: 5–20 Ω).
  • Check the signal voltage (should oscillate between 0.1 V and 0.9 V at stable operation).
  1. PCM circuit check:
  • Test continuity between the sensor and PCM (Elsawin diagrams required).
  • Check for absence of short to ground or +12V.
  1. Post-repair validation:
  • Clear codes, perform a drive cycle (conditions: warm engine, varying RPM).
  • Ensure short/long term trim values are within ±10% range.

Recommended Solutions

  • Lambda sensor replacement:
  • Use an OEM part (e.g., Bosch 0258006101) or certified equivalent.
  • Estimated cost: €150 to €400 (depending on Audi model).
  • Harness repair:
  • Replace damaged sections with high-temperature silicone wires.
  • Injector cleaning:
  • Use a certified fuel additive (e.g., Liqui Moly Pro-Line).
  • PCM update:
  • Visit an Audi dealer for reprogramming (specific SSP).

Audi Specific Cases

  • On Audi A4/A5/Q5 (2.0 TFSI engines), a TSB exists for recurring sensor errors related to outdated PCM calibration.
  • On Audi A6/A7 (3.0 TDI engines), check the AdBlue® system sealing (risk of sensor contamination).

What to Avoid

  • Ignoring code P1086 ➔ Risk of catalyst overheating and exponential repair costs.
  • Using non-calibrated “generic” lambda sensors for Audi ➔ Software compatibility issues.