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Home >> Hyundai >> 2004 >> Elantra GLS, Automatic >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Fuel System >> DTC Trouble Shooting Procedures >> DTC P0139: O2 Sensor Circuit Slow Responsive (Bank 1, Sensor 2) >> Inspection Procedures >> 3. Check Fuel Line Pressure
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3. Check Fuel Line Pressure

  1. Release the fuel pressure to install the fuel pressure gauge.
  2. After tightly installing the fuel pressure gauge to the fuel delivery pipe, start the engine and let it idle.
  3. Check fuel line pressure.

Is fuel line pressure normal? 

Yes: Proceed with ECM problem procedure.

No: Repair it.