heated o2 sensors wiring
 

Good morning everybody, Newbie here...

I just finished an angine and trans swap from a 2003 venture to a 2000 Monte Carlo. The swap was due to my monte carlo having too many miles and a bad transmision. I am using the PCM from the venture van and the harness from the Monte. The car is running ok, but I am getting a check engine light with code P0135. Basicaly the pcm is asking for the 03 o2 sensors wich are heated but my harness is not equiped for that. How can I hard wire the 03 o2 sensors into the PCM to clear the code?

More info if needed...
I can not use the montecarlo PCM because the transmission is not compatible and it will not shift from second gear..

I can not use the venture harness beacuse it is different plugs at the fuse box. Too big of a mess to make it work.

I am olso getting code B1001. Hopefully i can clear that code when I program my VIN into the PCM using HP tuners or EFI live (Tech II will not work. I tried)

Thanks in advance and sorry for the long post, just giving as much info as possible.

Wait.....so you're saying your Monte doesn't have heated o2 sensors??? The heated o2 sensors are the ones downstream from the catalytic converter(s).

I don't know what year GM went from non heated to heated o2 sensors.......but there is a way you can retrofit heated o2 sensors to get them to work with a non heated o2 sensor car. This is a fairly common mod that some people do for added performance/mileage.......do some research, I'm pretty sure you'll find something.

Oh.....and just FYI, the reason why the heated o2 sensor is called a "heated" o2 sensor is because it is electrically heated during cold starts rather than just itrelying on heat from the exhaust to warm the o2 sensor.

Well, at first I thought that my monte did not have heated o2 sensor but now Im thinking that it does. Maybe the wiring is just diferent from one pcm to another. I will do a search on how to bypass the heated part of the sensors. Has anybody ever have this problem with a full engine and trans swap? If so how did you fix it or work around it?

Well, BOTH O2 sensors are heated........

However, they are wired differently to their respective PCMs......the rear O2 sensor is wired the same way to the PCMs, but the front is not wired the same way in both PCMs.....

http://www.3800pro.com/forum/fwd-3800-engine-swaps/40565-wiring-diagram-help-o2-sensors.html

thanks for the replies. I found this thread from 5 years ago in another forum. Could it be this simple? Any ideas why this would or would not work?

That is basically what I said.......you would have to get schematics of both PCMs to rewire it correctly......

It's only the front that has to be changed....

Nice!!! Thanks for the help! Looks like I have a place to start and some experimenting to do. Now I know that I can use the monte carlo o2 sensor since it is heated and do some modefiyng to the plug on the harness. I just need to make sure of what pins I need to tap into on the pcm.

IF you don't have.......you should get an OBD scan tool which is capable of reading Real Time data.....specifically the live o2 sensor performance as it is occuring.

Yes, I have done that. Basicaly, it IS reading the info from the o2 sensor, but I am getting code p0135 wich is o2 heater circut. From what I understand the pcm is trying to heat up the sensor but it cant and thats why its giving me the code.