i have a probem with my o2 sensors. i have a 3.9L dakota, my truck only has 2 o2 sensors, in the last couple months i've replaced Both of my o2 sensors twice. my mechanic said the wiring harness isnt corroded or anything. so he suggested i replace my PCM. which i did, and now i have to take it to the dealership to get it reprogrammed. if i do this and the check engine light still comes on, what else could it be???? when the problem first started, the truck would bogg down and shut off when at idle. now, it runs fine and hasn't bogged in months! but the codes still keep coming on .
also, the truck only has 50,000 miles on it.

 

 

What brand of O2 sensors are you using? Dakota's have "issues" with Bosch. Use NTK or Denso, they are OEM.

What codes do you have?

 

Sounds like the PCM. I had two remanufactured PCM's, they were both bad. No drivability issues but couldn't shut the CEL off. One kept giving me bad injector codes and the next one I couldn't shut off the Park/Neutral CEL. I got fed up and bought a used one on ebay and bang...it worked! I don't think they check them out as good as they should. Also I think the numbers on mine were a 323AE and I used a 323AB used PCM and it was fine. I don't know why you would have to get it flashed at the dealer....it should work out of the box. Like Dan says the NTK's are probably the best ones to go with.

 

i use the bosch from autozone, the codes it's throwing are: P1491 P0132 P0135 P0141 .

 

I bought a used pcm from ebay as well and it didnt work in the truck but when we put my old one back in it worked. im assuming the pcm i bought was maybe a dud. i'm returning the pcm to the seller now. my pcm is 348AE

 

I just looked and im missing all my o2 sensor relays. Could that be making them not work as well?

 

The O2 relays control the downstream O2 sensors in the 4 O2 sensor emissions version. The upstream sensors are driven directly by the PCM. You don't need the relays.

P1491 is a radiator fan control relay circuit fault
P0132 1/1 O2 sensor shorted to voltage
P0135 1/1 O2 sensor heater failure
P0141 1/2 O2 sensor heater failure

As I said before, Dakota's hate Bosch O2 sensors. It may not be the entire problem but enough people have had problems that I wouldn't use them.

56040348AE is the correct PCM for a 50 state emission vehicle, 3.9L, and the 42RE.

 

I'll order some new o2 sensors, hopefully its the brand thats the Problem. Im tired of changing everything and nothing helping.