Inspection Procedures

CHECK HO2S AND ECM CONNECTORS
1. Check connectors for poor connection, misplaced, bent, loose or corroded terminals.
Are both connectors good?

Yes: Go to next step.

No: Repair or replace it.
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.
- 3 ~ 4 Ω at between 18°C and 28°C (64°F ~ 82°F)
Is resistance within specification?

Yes: Go to next step.

No: Replace HO2S.
CHECK POWER TO HO2S HEATER
1. Turn ignition switch to ON.
2. Measure voltage between the terminal 3 of 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 step.

No: Repair open or short to chassis ground in harness.
CHECK FOR SHORT TO GROUND IN HARNESS
1. Turn ignition switch to OFF and disconnect ECM connector.
2. Measure resistance between the terminal 4 of 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.