How do I replace the O2 seonsors??

[Khoshniat]

Hello,
I have a 1999 Dodge Grand Caravan 3.3L V6. I was given advice from the forum along time ago to replace my O2 sensors in order to get better fuel economy. I finally have the time to do the job. I was wondering if anyone had a diagram, or could tell me how to replace my O2 sensors. Thank you all so much for your help.

[Pwogaman]

The aft sensor is a breeze. Just look under the car - there it is. The wire goes up to the underside of the floor, just above the sensor. Pop out the grommet and plug the new one in.

The forward unit is more difficult. I got to mine (96 GC 3.3) by jacking the vehicle (use floor jacks on a level surface) and laying under with my feet facing forward. Reach an arm up along the cat. converter / exhaust path. The O2 sensor is right on top, just behind the exhaust manifold. There is also a plug up there which you can get to by gently pulling on the wire.

You should get a o2 sensor socket. You need it so you don't damage the wire.

[beerlover]

When I changed the front O2 sensor on my van, I had to remove the windshield wipers, then the plastic cowel under them that contains the actual wiper linkage and motor. That freed up enough space where I could reach over the top of the intake plenum and back to the sensor from the top side. I used a special socket with the cut up the side for the wires. It was a pain, but not too bad. I couldn't get a socket on mine from the underside.

Hit the sensor with some penetrating oil a few minutes before you try to loosen them up.

[Khoshniat]

Beerlover, what year and model is your van?


Thank you for your responses.

[beerlover]

Mine is a 97 Sport with the 3.3l

[Khoshniat]

I will try and replace the O2 sensors this weekend, thanks for your help.

[heatmiser]

I just replaced mine sat afternoon and dropped the catalytic converter and it was almost easy to get to I used a offset o2 socket from the bottom side

[heatmiser]

also its a 97 with a 3.8

[Rick99]

Unless you are getting codes, it is a complete waste of time and money to replace the sensor that comes after the catalitic converter. All that sensor does is check if the converter is working, the computer does not use it for engine management.

[sgillett]

I ground a slot in a 3/4" box wrench and went up from behind the motor. The plug on the wire was harder to r&r than the sensor on my '95 3.8. It was not a hard job at all IMHO. Rick99 is correct, don't replace the downstream sensor, it only tells the computer that the cat is bad, it has no input on mixture.

Scott

[spongie2001]

I could use a little more input on upstream/downstream os2 sensors. I have a 97 T&C LXI 3.8L - the check engine light is on, and I get a flash code 21 - (oxygen sensor signal doesnt change). I was going to order the part on line, but didnt realize there would be more than one type. How can I tell which one I need for my car?
upstream or downstream?
heated?
transitional low-emission vehicle?
how can I tell which sensor is putting out a code, and if I am getting a code from the downstream sensor, should I replace both the cat conv. and sensor? Any imput would be appreciated.

[Rick99]

Go to autozone and have them pull the codes. You should have a p-code that will tell you which sensor it's complaining about.

[RickMN]

Here's a link to an article on how oxygen sensors work. Gives you some of the theory in language you can understand.

A layperson's guide to oxygen sensors (http://free-auto-repair-advice.blogspot.com/2007/07/understanding-oxygen-sensorswhat-they.html)

[spongie2001]

Thanks for the imput - good article on how oxygen sensors work - just what I needed , a point in the right direction!