hello all,
I have a 2004 town and country, 3.8, check engine light came on, checked the code, it gave me a code that said my upstream o2 sensor was bad, changed it out, went a couple days, the light came back on, then it gave me this code, P0135, saying the upstream o2 sensor(cylinder bank 1) heater failure, what the heck is heater failure? any help would be appreciated. thanks

 

There's a heater built into each O2 sensor to quickly bring it up to the operating temp (around 600F) right after you start. Cuts down on pollution. You may have installed a bad sensor, you may have an open wire from the sensor to the PCM or the PCM may be bad. Most likely the sensor heater died. Did you use NKG or Denso? Bosch has a bad rep with these vans.

 

Prob used a BOSH o2 sensor

 

After a lot of research I think I found the problem.
I found a tech bulletin indicating that after July 09, 2004
O2 sensor resistance (ohms) was changed.
Before 2-4 ohms NTK 23568
After 7-10 ohms NTK 23566

(Initial fault was P0032 indicating a problem with the upstream O2 sensor.)
Needing replacement.

You can measure the resistance between the black wires on the sensor with an ohmmeter. (The heating coil)

I hope this helps somebody else.

 

Nice find ^^^^^^