99 Cav. eng light on O2 sen.

99 Cav. standard, eng light, secondary O2 sensor, replaced the sensor after the cat. cancelled the code. Light came back on. replaced the O2 sensor again (another new one) cancelled code O2 sensor showed operating OK eng. light came back on after 3 starts, code calls up secondary O2 sensor again. what the heck. any ideas from the gang.

maybe the sensor is doing its job and sensing a problem, but you dont fix the problem, you just keep replacing the sensor... bad catylic converter maybe?

99 Cav. standard, eng light, secondary O2 sensor, replaced the sensor after the cat. cancelled the code. Light came back on. replaced the O2 sensor again (another new one) cancelled code O2 sensor showed operating OK eng. light came back on after 3 starts, code calls up secondary O2 sensor again. what the heck. any ideas from the gang.

What engine and what is the code no.