I have a 2000 Durango 130,000 miles that hada bank 1O2 sensor error. I replaced the two 02 sensors and noticed that black carbon is coming out of the tail piper due to a rich fuel mixture. I think this caused the failure of the 02 sensors. Any ideas? Could a bad MAP sensor cause this?

 

Undo the neg side of the battery. Then apply the brakes to get the lights to come on to drain the PCM. Wait at least 45 seconds. Reconnect the neg on the battery. This should reset the PCM. You will need to drive the D for about 48 miles and cycle the key off and on at least 12 times to fully reset the PCM.

After this the new settings will take affect and the computer should tell the truck how to run. Basically, the truck is running rich. The computer needs to relearn the input and output settings.

You might want to do a full tune up as part of maintenance.

 

Can you help me understand why the PCM needs to be reset? One thing I didn't mention was that after I replaced the O2 sensors and cleared the error code, the Durango ran fine(no error codes for 1 1/2 weeks). Then the error code reappeared along with error codes 108 and 134. This is on a 4.7 engine.

 

You might want to check and make sury the o2 sensor is still pluged in.And also is making good contact

 

its pretty common that then wiring up the 02 sensor the mechanic will leave too much slack on the wires. This will make the wires rest on the pipe and eventually melt right threw them. ghog is right. you should recheck this first.

 

Found the problem. The Power Steer pressure switch is leaking PS fluid into the engine harnest and finding it's way down through the harnest and to the O2 sensors. When I pull the O2 sensor connectors, both had PS fluid in the connector. This seems to be causing the O2 sensors to crap out. What a freak mess Dodge has created.

 

You are only the second person that that has happend to. As far as I know it only happends on the 4.7L.

Yes that leak will take them out!

BTW<---- Resetting the PCM is needed if the computer can't reset the information that it is recieving. Sometimes they do that. On O2 sensors I encorage it to be done but it is not manditory. If problems continue I would surely do it.