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Home >> Hyundai >> 2017 >> Sonata Base >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 32 (Engine Control System Diagnosis - 2.0L (1 Of 3) (Except HEV)) >> DTC P0171: System Too Lean (Bank 1) >> System Inspection

System Inspection

WARNING: This page is about a different variant/trim than selected.

■ Air leakage Inspection 

  1. Visually and physically inspect for air and vacuum leaks in the areas listed below:
    • Vacuum hoses for splits, kinks and improper connections
    • Throttle body gasket
    • Gasket between intake manifold and cylinder head
    • Exhaust system between HO2S and three way catalyst for air leakage
  2. Has a problem found in this procedure?

    YES 

    NO 

    • Go to "Related Sensors Inspection" as follows

■ Related Sensors Inspection 

  1. Visually/physically inspect the following components:
    • Ensure that the HO2S is securely installed.
    • Silicon contamination. This contamination will be indicated by a white powdery coating on the portion of the sensor exposed to the exhaust stream and this will result in a but false (high) voltage signal
    • Fuel, engine coolant or oil contamination
    • Use of improper sealant
    • If contamination is evident on the HO2S, Fix the source of the sensor contamination before replacing the sensor to prevent future contamination. Go to "VERIFICATION OF VEHICLE REPAIR " procedure.
  2. Visually/physically inspect contamination or poor performance/poor connection of mass air flow sensor.
  3. Check if throttle position sensor'signal is in proportion to a gas pedal while driving.
  4. Check the ground state of the PCM.
  5. Has a problem found in this procedure?

    YES 

    NO 

    • Go to "Fuel Line Inspection" as follows

■ Fuel Line Inspection 

  1. Check the fuel line for following conditions:
    • Damage or leaking fittings and seals
    • Bent or restricted fuel line
  2. Has a problem found in this procedure?

    YES 

    NO 

    • Go to "Fuel Pressure Inspection" as follows

■ Fuel Pressure Inspection 

NOTE:
  1. Be cautious fuel is explosive and an empty fuel tank can still contain explosive gases. When working on fuel systems 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. IG "OFF". Remove Fuel Pump Fuse (20A).
  2. Start engine and wait until it stalls.
  3. IG "OFF". Install Fuel Pump Fuse (20A).
  4. Install the fuel pressure gauge to the delivery pipe with the fuel pressure gauge adaptor.
  5. Activate the fuel pump, and with fuel pressure applied, check that there is no fuel leakage from the pressure gauge or connection part.
  6. Measure the fuel pressure at idle.

    Specification:  440 ~ 460 kPa (4.48 ~ 4.69 kg/cm2 , 63 ~ 66 psi)

  7. Is the measured fuel pressure within specifications?

    YES 

    • Go to "Component Inspection" procedure below.

    NO 

    • Repair or replace according to the table below. Go to "VERIFICATION OF VEHICLE REPAIR " procedure.
      Condition Possible Cause
      Fuel Pressure is too low Fuel filter, fuel pressure sensor, in-tank fuel hose or the fuel pump, Fuel pump
      Fuel Pressure is too high Fuel pressure sensor, hose or pipe
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