Inspection Procedures

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.
CHECK HO2S HEATER RESISTANCE
1. Turn ignition switch to OFF position and disconnect HO2S connector.
2. Measure resistance between terminals 3 and 4 of the HO2S connector.
Fig 1: Measuring Resistance Between Terminals 3 & 4 Of HO2S Connector
Courtesy of HYUNDAI MOTOR CO.
- 9ohm at 20°C ~ 24°C(68°F ~ 75.2°F)
Is resistance within specification?

Yes: Go to next

No: Replace HO2S.
CHECK POWER TO HO2S HEATER
1. Turn ignition switch to ON position.
2. Measure voltage between terminal 3 of the HO2S harness connector and chassis ground.
Fig 2: Measuring Voltage Between Terminal 3 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.
CHECK FOR SHORT TO GROUND IN HARNESS
1. Turn ignition switch to OFF position and disconnect ECM connector.
2. Measure resistance between terminal 4 of the HO2S harness connector and chassis ground.
Fig 3: Measuring Resistance Between Terminal 4 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.