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.

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HOMESERVICE MANUALSCHEVROLET1987CAVALIER BASE, 4D WAGON, STANDARD, MR3REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSIS2.8L PFI TESTS W/CODESDIAGNOSTIC CHARTSCODE 13 - OPEN OXYGEN SENSOR CIRCUITDIAGNOSTIC AIDS

1987 Chevrolet Cavalier Base, 4D Wagon, Standard, MR3

Diagnostic Aids

1987 Chevrolet Cavalier Base, 4D Wagon, Standard, MR3SECTION Diagnostic Aids

Normal "Scan" tester voltage varies between 100 and 999 mV while in "closed loop". Code 13 will set in one minute if voltage remains between .35-.55 volt, however, system will go "open loop" in about 15 seconds.

Fig 1: Code 13, O2 Sensor Circuit, Schematic

RENDER: 1.0x

NO RELATED

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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.