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Home >> Pontiac >> 1988 >> LeMans Base, 2D Hatchback, Standard, M21 >> Repair and Diagnosis >> Engine Performance >> System >> 1.6L TBI System >> Adjustments >> Code 13, Open Oxygen Sensor Circuit >> Diagnostic Aids

Diagnostic Aids

Normal "Scan" voltage varies between .1-1.0 volt, while in "closed loop". Code 13 sets in one minute, if voltage remains between .35-.55 volt, but the system will go into "open loop" in about 15 seconds.

Verify a clean, tight ground connection for circuit No. 413. Open in circuits No. 412 or 413 will result in a Code 13.

Fig 1: Code 13, Schematic
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Fig 2: Code 13, Flowchart - Open Oxygen Sensor Circuit
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