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Home >> Kia >> 2017 >> Soul ! >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System Diagnosis - 1.6L T (3 Of 3) >> DTC P2251: O2 Sensor Reference Ground Circuit / Open (Bank 1 / Sensor 1) >> System Inspection
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System Inspection

Check Air Leakage 

  1. Visually/physically inspect the intake system for following items
    • Vacuum hoses for splits, kinks and improper connections.
    • Air leakage after throttle body.
  2. Have any problem been found?
    • Repair or replace it which has a problem, and go to "Verification Of Repair " procedure.
    • Go to "Check the fuel line" as follows.

Check The Fuel Line 

  1. Check the fuel line for following items
    • Connector status.
    • Damaged/bent/pressed/twisted fuel line.
    • Fuel leakage.
  2. Have any problems been found?

    YES 

    NO 

    • Go to "Check the fuel line" as follows.

Check Fuel Pressure 

NOTE:
  1. Be cautious that Fuel is explosive and an empty fuel tank can still contain explosive gases. When working on fuel system make sure to supply adequate ventilation to the work area. Do not smoke, and keep sparks and open flames away.
  2. The fuel system remains under pressure when the engine is not running. Release fuel system pressure before disconnecting any fuel line to reduce the chance of personal injury or fire damage to vehicle components.
  1. Start-up the engine and remove the fuel pump fuse and wait until engine stops.
  2. Install the fuel pressure gauge to the delivery pipe with the fuel pressure gauge adaptor.
  3. Install the fuel pump fuse and start-up the engine.
  4. Check that there is no fuel leakage from the pressure gauge or connection part.
  5. Measure the fuel pressure at idle.

    Specification:  480.5 ~ 500.1 kPa (4.9 ~ 5.1 kg/cm2 , 84.3 ~ 87.2 psi)

  6. Is the measured fuel pressure within specifications?

    YES 

    NO 

Condition Possible Cause
Fuel Pressure is too low Fuel filter, Fuel pump, Fuel pipe
Fuel Pressure is too high Fuel pump, Fuel pipe