O2 Sensor Inspection

■ O2 Sensor Signal Inspection 

1. Ignition "OFF".
2. Connect VMI to KDS/GDS and set up an oscilloscope as follow (4-channel);

   Channel A (+): Pin No. 3 (V_IP) terminal of Upstream O2 Sensor.

   Channel A (-): Ground

   Channel B (+): Pin No. 1 (Signal) terminal of Downstream O2 Sensor.

   Channel B (-): Ground

3. Ignition "ON" & Engine "ON".
   Fig 1: Screen Display - Upstream O2 Sensor And Downstream O2 Sensor Signal Waveform (Warm-Up Condition)

   Courtesy of KIA MOTORS AMERICA, INC.
   1. Approx. 2500 RPM.
   2. Fuel Cut after acceleration.
4. Is the measured value within specification?

   YES 

   • Go to next procedure.

   NO 

   • Carefully re-do this troubleshooting guide steps.
   • If no problems were found with the circuits or connectors, Replace the Downstream O2 Sensor and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
   CAUTION:

   • Install the component with the specified torques.
   • Note that internal damage may occur when the component is dropped or mis-treated.
   CAUTION:

   • DO NOT use a cleaner, spray, or grease to sensing element and connector of the sensor because oil component in them may cause malfunction or affects on sensor performance.
   • Sensor and its wiring may be damaged in case of contacting with the exhaust system (Exhaust Manifold, Catalytic Converter, and others).

■ MAP Sensor Inspection 

1. Ignition "OFF".
2. Connect VMI to KDS/GDS and set up an oscilloscope as follow (2-channel);

   Channel A (+): Pin No. 1 (Signal) terminal of MAP Sensor.

   Channel A (-): Ground

   Channel B (+): Pin No. 4 (TPS1 Signal) terminal of Throttle Body.

   Channel B (-): Ground

3. Ignition "ON" & Engine "ON".
4. Testing Condition: Idle to Acceleration.

   Specification:  Refer to below

   Fig 2: Screen Display - Normal MAP Sensor And TPS 1 Sensor Signal Waveform At Idle To Acceleration

   Courtesy of KIA MOTORS AMERICA, INC.
5. Is the measured value within specification?

   YES 

   • Go to next procedure.

   NO 

   • Carefully re-do this troubleshooting guide steps.
   • If no problems were found with the circuits or connectors, replace MAP Sensor and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
   CAUTION:

   • Install the component with the specified torques.
   • Note that internal damage may occur when the component is dropped or mis-treated.
   CAUTION:

   • Insert the sensor in the installation hole and be careful not to damage.

Fuel System Inspection 

1. Refer to "RELEASE RESIDUAL PRESSURE IN FUEL LINE " and release the residual pressure in fuel line.
   CAUTION: When removing the fuel pump relay, A Diagnostic Trouble Code (DTC) may occur. Delete the code with the KDS/GDS after completion of "Release Residual Pressure in Fuel Line" work.
2. Install the Special Service Tool (SST).
   1. Disconnect the fuel feed tube from the high pressure fuel pump.
      CAUTION: There may be some residual pressure even after "Release Residual Pressure in Fuel Line" work. Therefore, cover the hose connection with a shop towel to prevent residual fuel from spilling out before disconnecting any fuel connection.
   2. Install the Special service tool for measuring the fuel pressure in between the fuel feed tube and the high pressure fuel pump (Refer to below).
   Fig 3: Measuring Fuel Pressure In Between Fuel Tube And High Pressure Pump (1 Of 2)

   Courtesy of KIA MOTORS AMERICA, INC.
   Fig 4: Measuring Fuel Pressure In Between Fuel Tube And High Pressure Pump (2 Of 2)

   Courtesy of KIA MOTORS AMERICA, INC.
3. Inspect fuel leakage on connections among the fuel feed tube, the high pressure fuel pump, and the SST components with Ignition "ON".
4. Measure Fuel Pressure.
   1. Start the engine and measure the fuel pressure at idle.

      Specification:  Over 290 kPa (Over 2.9 bar, Over 2.95 kgf/cm² , Over 42.06 psi)

      NOTE: If the fuel pressure differs from the standard value, repair or replace the related parts (refer to the table below).

      Fuel Pressure	Cause	Related Parts
      Too Low	Fuel Filter Clogged	Fuel Filter
      	Fuel Leakage	Fuel Pressure Regulator
      Too High	Fuel Pressure Regulator Stuck	Fuel Pressure Regulator

   2. Stop the engine, and then check for the change in the fuel pressure gauge reading.

      Standard Value:  The gauge reading should hold for about 5 minutes after the engine stops

      NOTE: If the gauge reading is not held, repair or replace the related parts (refer to table below).

      Fuel Pressure (After Engine Stops)	Cause	Related Parts
      Fuel Pressure Drops Slowly	Leakage on injectors	Injectors
      Fuel Pressure Drops Immediately	Check valve of fuel pump stuck open	Fuel Pump

   3. Ignition "OFF".
5. Is fuel pressure value within specification?

   YES 

   • Go to "WIRING INSPECTION " procedure.

   NO 

   • Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.