My car is a 2001 Monte Carlo 3.4l

The check engine light came on a month ago and came up with the code of the second o2 having a heater circuit malfunction. So I had it replaced along with the cat just recently. I drove the car probably 10 miles trying to complete the drive cycles and now this time the code comes up different with the P0140 code. Not exactly sure what the problem is now I checked all the fuses and they are fine. Cant think of anything else to be the problem, please help.

 

try cleaning the MAF sensor

 

Just tried cleaning the MAF sensor, the light still came on and reading same code. It comes on in like 15 miles of driving.

 

I would check the wire harness from the 02 sensor to where it plugs in the harness. look for broken wires or a short ... also find out what brand the 02 sensor is, GM is fussy.. also if the converter you had replaced was aftermarket it may also trip that code. That code is a catalytic efficiency code and wont effect how the car runs but may cause ya to fail emissions test...if you have to do that sort of thing, in the end if you don't have to have emission testing you can just live with it. if you can stand having the money light on LOL I had a 96 gmc truck with that code and just ran it.. it ran just fine. There is a way I believe yu can have the PCM reprogrammed to ignore that. Maniac would know Oh also I think there is a fuse for that 02 sensor heater circuit....you could also check that out.

 

I would second the whole brand thing on the O2 sensor/ converter. I've had several aftermarket components not work properly and replaced them with ACDelco and then they worked fine. Our cars a really touchy when it comes to aftermarket

 

Sorry for not replying for a while. Turns out the problem was the wires for the 02 sensor, they ended up being broken.