Code 26, Oxygen Sensor Circuit Rich Exhaust Indicated: Notes

WARNING: This page is about a different car, the 1992 Geo Prizm. However, it is still accessible from the selected car via links, so may be relevant.

O2 sensor produces a varying voltage as engine reaches normal operating temperature. Voltage will vary between .1-.9 volt. O2 sensor will not produce voltage until sensor reaches 600°F (316°C). When sensor is less than this temperature, an open loop condition exists.

NOTE: Test numbers refer to test numbers on diagnostic chart.

This checks for an intermittent Code 26. Code 26 will set when oxygen sensor signal voltage on Black wire remains greater than .7 volt for 30 seconds or more with system in closed loop, engine after-start run time is one minute or more, and throttle angle is 3-45 percent.