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 OFF and disconnect HO2S connector.
2. Turn ignition switch to ON.
3. 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. 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.