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.
2011 Hyundai Equus SignatureFACTORY OEM SERVICE PROCEDURE
Component Inspection
- Replace the HO2S.
- Clear DTC with GDS.
- Start the engine and warm it up until the radiator fan comes on (more than at least 10 minutes).
- Drive at a steady speed between 45-55 mph (72-88 km/h) for 120 sec.
- Stop and then maintain idle state.
- Check if O2 sensor monitoring readiness is complete.
- Does the scan tool show DTC P0133?
YES
- Substitute with a known - good ECM and check for proper operation. If the problem is corrected, replace ECM and go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
- Troubleshooting is finished.
Factory Service Tools
Use the Manual With the Right Hardware
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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.