DTC P0153-O2 Sensor 2/1 Slow Response: Notes

Fig 1: O2 Sensor 2/1 Circuit - Circuit Diagram

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article.

Theory of Operation 

For an aged O2 sensor, the response rate to the air/fuel change is slower than when it was new. The O2 sensor tends to move less with the same air/fuel changes in a given time frame. Therefore by observing the activity of voltage readings from the upstream O2 sensor, the quality of the O2 sensor can be detected. 

• When Monitored: 

  Vehicle is started and driven between 20 and 55 MPH with the Throttle open for a minimum of 120 seconds. Coolant greater than 70°C (158°F). Catalytic Converter Temp greater than 600°C (1112°F) and EVAP Purge is active. 

• Set Condition: 

  O2 Sensor response is too slow for a calibrated amount of time. Two Trip Fault. Three good trips to turn off the MIL. 

Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding.