Back to 2014 Subaru BRZ

2014 SUBARU BRZ

2.0L H4AWDMANUALgas
Founding sponsor spot is openYour name on every procedure for this vehicle, permanently.Sponsor — $30 →
Repairs0Labor564Torque5830Fluid10DTC903Battery0Maintenance0Recalls0
P1090moderate severityPowertrain

Tumble Generator Valve 1 RH Stuck Open

on 2014 Subaru BRZ 2.0L H4 · 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

  1. Command TGV closed with scan tool and monitor position sensor
  2. Inspect TGV valve for carbon buildup or physical obstruction
  3. Check TGV actuator motor operation
  4. Inspect linkage for damage
  5. 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

Building an app?
Free API access to all this data — 50 requests/day, no card required.
Get an API key →
Run a shop?
Manage repairs, estimates, and customers with ShopBase — $249/mo, all features included.
Try ShopBase →