P1086 SUBARU Possible Causes
- Faulty tumble generator position sensor
- Tumble generator position sensor harness is open or shorted
- Poor electrical connection in tumble generator position sensor circuit
- Faulty tumble generator valve
- Faulty Engine Control Module (ECM)
How to Fix P1086 SUBARU Code?
Start by checking the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
Illuminated engine light (or service engine soon warning light)
P1086 SUBARU Meaning
The tumble generator system uses an electronically controlled throttle valve in each intake port. During cold idle, the tumble generator system will redirect the air charge through another port. These ports have a finishing characteristic that causes the air/fuel mixture to swirl and tumble considerably and creates better combustion. This results in better idle quality, cleaner emissions, and easier cold starts.
Once the vehicle is warmed up, the tumble generator system will be disabled and the intake air charge will be directed through the standard intake ports.
The tumble generator sensor is responsible for measuring the position of the tumble generator throttle valves. When the throttle valves open or close, the signal voltage varies accordingly at the position sensor.