DODGE RAM FORUM banner

O2 sensor cause check engine light to come on

16K views 21 replies 9 participants last post by  E.L.D. 44 
#1 ·
I have a 2004 ram 5.7 hemi, I recently put a k&n cai, pacesetter long tube headers with not cats and three inch all the way to flowmaster super 44 mufflers, I also have a superchips cortex programmer. My problem is once I instaled the exhause sytem and started the truck my check engine light came on. My programmer says that the O2 sensors are hot, my rear O2 sensors I did not put back on. What can I do to solve the check engine light without putting the cats back on, and will any of this effect the performance and reliability of the truck? Does anyone also know of a place in texas where I can get a custom tune for this truck?
 
#17 ·
I've had a lot of customers that have regretted cutting the wires for the 02 sensors.
There are "variable voltage resistors" and that's probably why there is no plug and play 02 simulators.
If you get longtubes it's probably better to get the 02 extensions if needed.

I sell the rear 02 sensor spacers drilled and assembled. You can do this yourself also.

http://moesperformance.com/index.php?main_page=product_info&cPath=13_1064&products_id=4111
 
#7 ·
use 2 non foulers per 02 sensor (rear), stuff the bottom one with steel wool, the top one has to be drilled out a little so the 02 sensor can thread in. I have it on mine and i run lt headers, gutted cats, no codes..
 
#15 ·
I just wanted to make a quick post and thank all that have contributed to this thread and similar ones. I am fairly new to the forum as I very recently bought my first Ram ever...a Silver 2001 1500 4x4 5.9L gasser. Fell in love with the truck on sight and first test-drive convinced me it was mean't to be. I have to admit though, in all of my excitement I didn't do all of my homework. I bought the vehicle out of state and upon getting it back home realized the dual exhaust that was already there (sounds amazing) had no cats. Much to my amazement I passed the inspection with flying colors. However, a couple of days ago my check engine light came on. I scanned it and found it to be a P0138 trouble code. It was the dreaded O2 sensor that was supposed to be behind the cat. Great! What was I going to do about that? I came straight to the forum and started looking at the different threads trying my best not to have to spend who knows how much to change my exhaust system. Thanks to you guys I have fixed the problem for a whole $5.00 in spark plug non-foulers! Whoever came up with this idea is a freakin genius! You guys are the greatest! It's such a relief knowing that we have a community like this that actually cares enough to share such useful info. Thanks again to all who contributed!
 
#18 ·
I have a similar problem after installing a cat back flowmaster with o2 low voltage I believe just the one after the cat is giving me the problems (my cat is stock unmodded). Im assuming I have to replace it does anyone have a link to a good cheap source for o2 sensors that would work? Im seeing prices all over the place some with the plug in connector some you have to splice into the connector. Any thoughts would help.
 
#21 ·
If you dont have the 02 sims,then your going to have more codes,so buy them and put them on anyway.

Yor code is more of a wiring code,either you burnt a wire,or its hooked up backwards or not all the way plugged in.You should never twist or pull on 02 sensors wires,make sure your header didnt burn the wires.

Front 02 codes are much worse than rear 02 sensor codes,cause they will effect how the truck runs.
The 02 sims are a must with the ARH headers.
Hope that helps a bit.
Good Luck.
 
#22 ·
passenger side wiring extension had a connector pushed out the back. replaced and solved that code. installed O2 plug extensions that I got from Moes and that solved my rear codes. I am code free now! Thanks. I don't know why but I really dont think my MDS was functional with my cel light on. Even when just the rear code was on my gas mileage dropped. Maybe its a new feature on the 11 computer to turn it off with a cel?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top