Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

2004 Hyundai Tiburon Base, StandardFACTORY OEM SERVICE PROCEDURE

Inspection Procedures

CHECK HO2S AND ECM CONNECTORS
1. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Are all connectors good?

Yes: Go to next

No: Repair or replace it.
CHECK FOR OPEN IN HARNESS
1. Turn ignition switch to OFF position and disconnect HO2S and ECM connector.
2. Measure resistance between terminal 1 of the HO2S harness connector and terminal 37 of the ECM harness connector.
3. Measure resistance between terminal 2 of the HO2S harness connector and terminal 42 of the ECM harness connector.
Fig 1: Measuring Resistance Between Terminal Of HO2S Harness Connector & Terminal Of ECM Harness Connector
Courtesy of HYUNDAI MOTOR CO.
- Specifications: below 1ohm
Does each resistance indicate open?

Yes: Go to next

No: Repair open in harness.
CHECK HO2S SIGNAL WAVEFORM
1. Reconnect the HO2S and ECM connectors.
2. Warm up the engine to normal operating temperature.
3. Using a Hi-Scan (Pro), monitor the HO2S signal waveform.
Do the rear HO2S signals fluctuate between 0V and 1V?

Yes: Proceed with ECM PROBLEM PROCEDURE .

No: Replace HO2S.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.