Component Inspection

■ Upstream Heated Oxygen Sensor Visual Inspection 

1. Ignition "OFF" and disconnect HO2S (S1) connector.
2. Check that HO2S (S1) is not contaminated or damaged by foreign materials.

■ Upstream Heated Oxygen Sensor Performance Inspection 

1. Warm up the engine to normal operating temperature.
2. Connect VMI to KDS/GDS and select "Oscilloscope".
3. Connect Channel A positive probe to Pin No. 1 (Nernst Voltage) and Channel A negative probe to Pin No. 4 (Trim Resistor).
4. Connect Channel B positive probe to Pin No. 3 (Virtual Ground) and Channel B negative probe to Pin No. 6 (Pumping Current).
   Fig 1: Screen Display - Approx. 2000RPM (A), 3000RPM (B) & Fuel Cut (C)

   Courtesy of KIA MOTORS AMERICA, INC.

   A and B: Approx. 2000RPM and 3000RPM

   CH.1 - Nernst Voltage & Trim Resistor: - 0.10 ~ 1.12V

   CH.2 - Pumping Current & Virtual Ground: -0.35 ~ 0.59V

   C: Fuel cut

   CH.1 - Nernst Voltage & Trim Resistor: 1.10V

   CH.2 - Pumping Current & Virtual Ground: 0.59V

■ Confirm Part Inspection 

1. Does the HO2S upstream (S1) operate properly? (Check variation)

   YES 

   • Go to "Verification of Vehicle Repair " procedure.

   NO 

   • Carefully re-do this troubleshooting guide steps.
   • If problem still occurs, replace HO2S upstream (S1) and then go to "System Inspection" procedure.