Inspection Procedures

1. CHECK HO2S AND ECM CONNECTORS
   1. Check HO2S and ECM for poor connection, misplaced, bent, loose or corroded terminals.

      Are both connectors good? 

      Yes: Go to next

      No: Repair or replace it.

2. CHECK HO2S HEATER RESISTANCE
   1. Turn ignition switch to OFF and disconnect HO2S connector.
   2. Measure resistance between the terminals 3 and 4 of HO2S connector.
   Fig 1: Measuring Resistance Between Terminals 3 & 4 Of HO2S Connector

   Courtesy of HYUNDAI MOTOR CO.
   • 9ohm at between 20°C ~ 24°C (68°F ~ 75.2°F)a

   Is resistance within specification? 

   Yes: Go to next

   No: Replace HO2S.

3. CHECK POWER TO HO2S HEATER
   1. Turn ignition switch to ON position.
   2. Measure voltage between terminal 4 of the HO2S harness connector and chassis ground.
   Fig 2: Measuring Voltage Between Terminal 4 Of HO2S Harness Connector & Chassis Ground

   Courtesy of HYUNDAI MOTOR CO.
   • Specification: approximately B+ 

   Is voltage within specification? 

   Yes: Go to next

   No: Repair open or short to ground in harness.

4. CHECK FOR SHORT TO GROUND IN HARNESS
   1. Disconnect ECM connector.
   2. Measure resistance between terminal 3 of HO2S harness connector and chassis ground.
   Fig 3: Measuring Resistance Between Terminal 3 Of HO2S Harness Connector & Chassis Ground

   Courtesy of HYUNDAI MOTOR CO.
   • Specification: infinite 

Does resistance indicate open? 

Yes: Proceed with ECM PROBLEM PROCEDURE  .

No: Repair short to chassis ground in harness.