P1090moderate severityPowertrain
Tumble Generator Valve 1 RH Stuck Open
on 2015 Subaru Legacy 3.6L H6 · AWD
What this code means
The PCM has detected that the Tumble Generator Valve 1 on the right-hand cylinder bank is stuck in the open position. The valve should close at low engine loads to create intake air tumble.
Symptoms
- Check Engine Light
- Reduced combustion efficiency at low loads
- Slightly rough idle
- Higher emissions
Common causes
- Carbon buildup preventing valve closure
- Faulty TGV actuator motor
- Broken TGV linkage
- TGV shaft binding
- Actuator wiring issue
Diagnostic steps
- Command TGV closed with scan tool and monitor position sensor
- Inspect TGV valve for carbon buildup or physical obstruction
- Check TGV actuator motor operation
- Inspect linkage for damage
- Test actuator wiring
Repair notes
Clean carbon from the TGV valve; replace the TGV actuator if the motor or linkage has failed.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1