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2014 SUBARU BRZ

2.0L H4AWDMANUALgas
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P1086low severityPowertrain

Tumble Generator Valve 2 LH Position Sensor Low

on 2014 Subaru BRZ 2.0L H4 · AWD

What this code means

The PCM has detected a low-voltage condition on the Tumble Generator Valve 2 left-hand position sensor circuit. The TGV system creates tumble motion in the intake air to improve combustion efficiency and reduce emissions at low loads.

Symptoms

  • Check Engine Light
  • Minor reduction in fuel economy
  • Slightly higher emissions

Common causes

  • Faulty TGV position sensor
  • Wiring short to ground in sensor circuit
  • Corroded TGV sensor connector
  • Damaged sensor due to heat exposure

Diagnostic steps

  1. Check TGV 2 LH position sensor voltage on scan tool
  2. Inspect sensor connector for corrosion
  3. Test sensor wiring for shorts to ground
  4. Check 5V reference at sensor
  5. Compare readings between left and right TGV sensors

Repair notes

Replace the TGV position sensor or repair the wiring if shorted to ground.

Other Powertrain codes on this vehicle

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