MIL ON - Oxygen Sensor Fault Code Set

90hyundai01 Subject

RECURRING CHECK ENGINE LIGHT

Group

ENGINE

Number

016

Date

APRIL, 1989

Model

SONATA




Condition/Complaint: Recurring illumination of the "check engine" light, accompanied by an oxygen sensor fault code in the ECU self diagnostic memory.

Cause: Poor alternator to engine ground and excessive resistance in battery ground circuit.

Correction: 1) Remove the alternator from the vehicle and clean the mounting surfaces on both the engine block and the alternator. Make sure to remove any corrosion on the engine block mounting pad and the alternator steel sleeve. Apply a light coat of dielectric grease to all of the mounting surfaces and reinstall the alternator.

2) Replace the battery ground cable. Be sure to thoroughly clean the negative battery post and the bellhousing mounting surface before installing the new ground cable.