Anyone have any info on code P1129? I am pulling that code on my pocketlogger and cant find any info. HELP PLEASE! This thing is killing me :rolleyes

Thats a manufacturer specific code, but it's not listed with the chrystler ECU. The generic meanin of that code is
P1129 - Downstream Heated O2 Sensors Swapped

Not sure exactly what thats supposed to mean, but thats the best I could find. http://www.troublecodes.net/OBD2/

Have you tried resetting the ECU? Try that and see if it goes away.


95 Eclipse RS : 5 speed
15.943 @ 86.48mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

Hmmm, I have reset the ECU MULTIPLE times. Always comes back, any recommendations on how to fix it? Anyone???

This is a Ford article, but it's the only document I could find that explains anything about this code http://www.thedieselstop.com/faq/9497faq/tsb/tsb/files/010907.pdf

I think the first thing I would do is check out anything that I was working on when the code started to appear. When did this code start appearing? Were you working in or around the ECU harness? How bout the exhaust - did you put on a new exhaust or something like that? Make sure that all the wires are good and that all of the connections are still connected around where you were working on it.

The thing that's really weird about this code is that we only use one bank(bank 1). It's an I-4, one upstream and one downstream - both on bank one. This code is saying that the downstream(rear) one is on the wrong bank....well we only use the one bank - that's why it's wierd. I would probably try replacing the rear o2 sensor - or possibly getting a o2 simulator for it(cheaper and will do the same thing). I have a rear o2 simulator on my car(to fix a completely unrelated issue that I had). Got it from casepers electronics - 104037 O2 SIM-RETROFIT http://www.casperselectronics.com/cgi-local/store/commerce.cgi?product=IMPORTS

If a new rear o2 sensor(or simulator) doesn't fix the problem, then I would think the problem is in the wiring harnes or with the ECU itself.


95 Eclipse RS : 5 speed
15.943 @ 86.48mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

Once again thanks for the help on locating that code, but I figured out the problem. My pocketlogger is pulling that code on everybody's car. KSeclipse had a CEL and my pocketlogger pulled the same P1129 code that mine did and he knew that was not the right code. I took the car to autozone and they pulled a P0420 Catalytic Efficiency Below Threashold in Bank 1. So my pocketlogger software is not working correctly :( Oh, well. I believe the code I pulled is reffering to either O2 sensors (which I have already replaced), and the cat. Am I correct? Either way I am going to try and get a new cat on this weekend. Thanks again

You are both pulling the same code and calling it a different name. If the rear O2 sensor is sending a funny readin to the ECU, it's going to trip a code. And that code is going to tell the ECU that the cat isn't functioning properly.

That's what the downstream O2 checks. So wether you call it bad downstream O2 or inefficient cat, they are both reffering to the reading from the downstream O2.

I would suggest checking the downstream O2 (check manual you can check it with a multimeter). before you replace any sensors or replace your cat.



15.9 @ 86.7mph

Injen CAI, 55mm TB, P&P Intake, Crower Cams, Hooker Header, ERT/Catco Cat, GS-T Muffler, AFX UDP, Crane Ign Amp, S-AFC

Well, the thing is....I have already replaced both O2's with brand new ones after I got that code. But I guess I can check the new ones with my volt meter. Thanks for the info, what do you mean by we both are pulling the same code? Pocketlogger and Autozone? Why would they call it different? Anyway, I notice you have a catco cat, do you happen to have the part number :)

It's a 2.5" Cat-Co High Flow universal welded up by ERT. You can see them on their site http://www.exileracing.com $60.00 for the universal.

Both code readers are pulling a code that says they don't like the rear O@ voltage, just calling it by a different name. If you've already replaced the O2 sensor, then the cat is probably gone.



15.9 @ 86.7mph

Injen CAI, 55mm TB, P&P Intake, Crower Cams, Hooker Header, ERT/Catco Cat, GS-T Muffler, AFX UDP, Crane Ign Amp, S-AFC