P1086 — Tumble Generator Valve #2 (LH) Position Sensor Circuit Low Input
CAUTIONIs it safe to drive? Drive gently and get it looked at soon — it can worsen or fail inspection.
What P1086 means
This is a manufacturer-specific code — its meaning depends on the vehicle’s make (see below).
What P1086 means on specific makes
Subaru CAUTION
The Tumble Generator Valve (TGV, Subaru's intake-air swirl flap) position sensor on the left-hand bank is reading low. TGVs improve cold-start emissions/combustion; a stuck flap or sensor fault sets this.
- Failed TGV position sensor / TGV assembly ($150-400)
- Carbon-stuck tumble valve
- Connector/wiring fault
Check first: Check TGV position sensor signal and that the flaps move freely; carbon sticking is common. Related codes cover the other valve/bank (P1083/P1084/P1085).
Source: obd-codes.com/trouble_codes/subaru, troublecodes.net