Jeep Commander Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter #1
I have an 06 5.7 Commander with a check engine light for code P0430.
I monitored on the Torque app and see fluctuating voltage on both sensors, both sides of the cat. I did a visual, and there's a nickle sized dent in it. It appears the cat is bad.
So now my problem. I live in Calif, so the OEM cat is not cheap. I had no luck finding an aftermarket that is legal.
I did find an entire exhaust system off an 08 5.7 Challenger that was converted to an SRT8 at 35K miles. It appears to be the same cat, but I don't know. He wants $200 for everything.
Can anyone help me with options?
 

·
Registered
Joined
·
3,037 Posts
The O2 sensors are switching sensors, it is normal to see fluctuating voltage on them.

When the PCM does its periodic check of the Catalytic Converter, it compares the output of both the upstream and downstream O2 sensors. If the Cat is working correctly, there will be difference in O2 and a difference in the output of the sensors. That difference would be a difference in the fluctuation of voltage.

Its possible, but NOT likely you could have a bad O2 sensor, but you should get other codes for that.

The pipe from the exhaust manifolds to the exhaust are all a welded single unit, including the cats. I don't see how you can replace cats other than replacing the entire pipe, other than cutting and welding.
 

·
Registered
Joined
·
22 Posts
Discussion Starter #3
When I say they both fluctuate, I mean upstream is up and down, like it should be, and downstream is also up and down, where it should be a steady line if the cat is working. Unless I understand it wrong.
Bank 1, normal side:


Bank2, bad side:
 

·
Registered
Joined
·
52 Posts
this is what i would do if i were you.

i never seen the bottom of a 5.7 but from what i seen in the past online is that they have possibly 2 cats and 4 oxygen sensors, i may be wrong, i don’t even know what i have underneath my 3.7L anyways i feel its to early for the cat(s) to go bad for an 2006. but since you metion a dent on one of them, slighty tap that one with a small mallet, and if you here a rattling, then possibly the honeyweb inside that cat collasped.

so even tho your diagnostics of the 02 sensors says they seem ok, I would replace ALL of them,( some manufactures recommend replace o2s ever 70k miles, plus they increase gas mileage) and reset the light and keep track of how many miles its driven before the check engine light comes on( hopefully not).
From my research with Hondas and Toyotas the check engine light comes on after 50 mile after one has reset it.
So lets say the check engine light came on again..and it’s the same p0420..
I wouldn’t worry about it till 2 weeks of the smog test requirement is due.
Anyways I would call around exhaust shops and get quotes, because some shops can or are able to cut and weld the cats out and replace them with legal aftermarket cats that meet the requirement. Which is way cheaper. If you don’t find that or its way to expensive,
Then I would suggest you put a non chalant Ad on craigslist like stating that ur jeep needs to Pass smog and that you could pay up to whatever you feel is worth it (eg 150 cash). have some on put the ad in spanish for you if you don’t know spanish, or if you know a Hispanic person goto the ghetto side of town and have them goto a smog guy and tell them they have cash in hand and if they can “pass it”, just don’t go with them because once the smog guy sees you he won’t take that chance,( my friend lost his smog licensee because he was dealing with an undercover, but that’s a different story)
Anyway if that does not work, remember the 50 miles I was telling you about and to keep track of the miles to see when the check engine light turns on? Well lets say it turns on at 50, reset the light and drive it for 44 miles (this is just an example) straight to the shop your going to smog it at, if all is good after the smog dude connects the smog machine connector to the obd2 port and begins running the wheels u should be good, it will pass smog because the 44 miles is enough to set the ECM parameters and enough for the smog machine to detect the parameters, but not enough to set the engine light. Don’t show up to the smog shop with 10 miles the machine will reject that..and the smog guy will tell you it must be driven some more, and ur time will be wasted. Or smog guy will force the run and tell you it didn’t pass…and there goes ur 1st chance. hopfullly ur jeep is properly tuned-up and a recent oil change made so it can pass the compound tailpipe test
Well good luck

Ps I forgot to mention I believe in CA, Cats have a 10 year manufacture warranty, u might want to check it out, I don’t know all the fac. I live in SO CAL and I know the struggle too well.
Good luck
 

·
Registered
Joined
·
22 Posts
Discussion Starter #5
Good stuff. I don't know about the covert mission to the Hispanic ghetto, though. Lol. I know what you mean though I just bought a 2000 Mustang from a car lot in the part of town where all the signs are in Spanish where the guy barely spoke English, and the car had just passed his smog. Even though it has illegal aftermarket mods that I know would make it fail visual inspection at least.
But I think I'll follow your advice about the rest though. I'll start with swapping the o2 sensors and try to test it.
The muffler shops I've called all said there's no aftermarket for the 5.7 Commander. But I'll dig deeper if it fails smog.
Great info. Thanks alot. I refuse to pay 5x the price for the exact same cat just because I live in Calif.
 

·
Registered
Joined
·
31 Posts
Good stuff. I don't know about the covert mission to the Hispanic ghetto, though. Lol. I know what you mean though I just bought a 2000 Mustang from a car lot in the part of town where all the signs are in Spanish where the guy barely spoke English, and the car had just passed his smog. Even though it has illegal aftermarket mods that I know would make it fail visual inspection at least.
But I think I'll follow your advice about the rest though. I'll start with swapping the o2 sensors and try to test it.
The muffler shops I've called all said there's no aftermarket for the 5.7 Commander. But I'll dig deeper if it fails smog.
Great info. Thanks alot. I refuse to pay 5x the price for the exact same cat just because I live in Calif.
Have them look up 06 Jeep Grand Cherokee with the 5.7L engine.
They use the same cat but there is more aftermarket support for the Grands.
I would replace the O2 sensors first though.
 
1 - 6 of 6 Posts
Top