P0432 immediately after changing O2 sensors

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May 8, 2016 | 06:28 PM

#16

97grand4.0

CF Veteran

Joined: Nov 2015

Posts: 2,856

Likes: 201

From: syracuse ny

Year: 1997

Model: Grand Cherokee (ZJ)

Engine: 4.0, new lifters valve job with new springs and exhaust valves, preload set with shims

Quote:

Originally Posted by CCKen

The PCM gets a little funny when changes are made that upsets its predetermined set points. Introducing new O2S' may have given it fits - for awhile.

Do like Jeep Driver suggests and clear the code and drive it. Take it out on a freeway run to clear its throat.

I second that. In fact I would also say the pcm's are off the chart sensitive to anything but the exact mopar parts they are calibrated for. But I do think it is comparing the new readings to the old. Clear it and drive it.

May 17, 2016 | 03:41 AM

#17

Ralph77

CF Veteran

Joined: Oct 2015

Posts: 7,517

Likes: 1,626

Year: 2000

Model: Cherokee (XJ)

Quote:

Originally Posted by Sizemic2

Thanks for replies! Ralph, i do have a bit of a stumbling idle, always have, but i don't know how much of that is vacuum leak or just old inline engine technology. I replaced tps, iac, and cleaned the TB a few weeks ago and the idle was exactly the same, but no codes. That MAP tube did look pretty rough, but it didn't appear to be cracked. I'll have a closer look at the manifold bolts & gasket. I may throw in the old downstream O2 sensor as well, just to isolate the issue.

The CEL didn't come on right away, it came on when i accelerated quickly from a stop at a red light about 10 minutes from my house. And i drove it quite a while the day before after changing the sensors. An exhaust or vacuum leak would have been there the whole time, so it just seems like odd timing. I'll post updates on the situation.

So my P0432 came back. After about 550 miles. Thinking of trying one of two things next. Replacing the rear downstream O2 sensor, either with the old one or defecting the newer one and put in a brand new one, or trying that Catakleen snake oil crap. Neither of which I think will work but we will see. Will post further updates.

May 17, 2016 | 06:16 AM

#18

97grand4.0

CF Veteran

Joined: Nov 2015

Posts: 2,856

Likes: 201

From: syracuse ny

Year: 1997

Model: Grand Cherokee (ZJ)

Engine: 4.0, new lifters valve job with new springs and exhaust valves, preload set with shims

When I replaced my cat I got a big boost in performance. Of course the california cat was the one I was supposed to use. I did notice that by reusing the factor cali 02 it set a code with the new cat. I replaced it, and it stopped setting the code. You have to match the sensor to the cat.

May 20, 2016 | 02:44 AM

#19

Ralph77

CF Veteran

Joined: Oct 2015

Posts: 7,517

Likes: 1,626

Year: 2000

Model: Cherokee (XJ)

Well tried the Catakleen crap. Have a friend who said he tried it and it did not work. But he has a friend with a Jeep who used just to get through emissions and figured he would fix the Jeep right later. Turns out it worked for him though and he never did anything else to his Jeep. I guess we will see.