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Oxygen Sensor: Testing and Inspection

Scan Tool Parameters

A scan tool has several parameters that indicate the state of the exhaust gases: Oxygen Sensor One (O2S 1) voltage, Short Term (S. T.) fuel trim, and Long Term (L. T.) fuel trim.

Oxygen Sensor Circuit Problems

A problem in the 02S 1 circuit should set a DTC P0134 (open circuit), DTC P0131 (lean exhaust indication), or DTC P0132 (rich exhaust indication). A faulty or lazy sensor will set a DTC P0133 (slow response) or a DTC P1133 (insufficient switching). Testing and Inspection