...when these three codes appear P0134, P0420 & P0441, where should I start looking to try and solve them, thanks!

 

Got exactly those 3 codes. Check purge valve if working or replace it but check tubes if no leaks. Check prior codes related to O2 sensor to know which O2 need to be checked or replaced. 0420 bad news for me. Need new cats driver side. Good Luck

 

...thanks for the quick reply, but how did you check if "purge valve" worked correctly or not? ...and how did you check if there were leaks? ...as per the O2 sensors, hoe did you check them out too? ...thanks again!

 

P0134 O2 sensor circuit No activity detected Bank 1 Sensor 1. Meaning your o2 sensor is dead or not plugged in.

P0420 Bank 1, drivers side, cat is below standards. Meaning your driver side cat is dying, probably from the faulty O2.

p0441 purge valve. Replace faulty purge valve

 

...thanks for the reply Daedrix ...so if I understood right and O2 Sensor is actually plugged in, I should replace it cuz it should be dead? ...after replacing the "dead" O2 Sensor, P0420 may go away or it's death prolonged? ...the"purge valve" code would appear only if valve is "dead", and replacing it should get the code cleared? ...again, thanks for your response! ;-]#

 

No he is saying that the O2 sensor probably caused your engine to run badly and ruined that catalytic converter.

The purge valve is on the driver side of the upper intake of your engine. It is black and has a hose entering from the front and exiting the back. It also has an electrical connector on it so you'll want to first make sure that is connected. Then check the hoses for any cracks. In dire situations you can blow smoke in the hose and it might show cracks but the hose runs almost the length of the truck. A new one is cheap and there is a Hyundai part that is the cheapest and the same thing (I don't know the part number but if you Google it you'll find to and they have them at all parts shops).

The rear O2 sensor measures cat efficiency so it is possible that it is out of whack too but the more likely issue is a bad cat. In that case you either have to pay a shop to put a new one in or get a new y pipe that has both cats on it.

 

No he is saying that the O2 sensor probably caused your engine to run badly and ruined that catalytic converter.

The purge valve is on the driver side of the upper intake of your engine. It is black and has a hose entering from the front and exiting the back. It also has an electrical connector on it so you'll want to first make sure that is connected. Then check the hoses for any cracks. In dire situations you can blow smoke in the hose and it might show cracks but the hose runs almost the length of the truck. A new one is cheap and there is a Hyundai part that is the cheapest and the same thing (I don't know the part number but if you Google it you'll find to and they have them at all parts shops).

The rear O2 sensor measures cat efficiency so it is possible that it is out of whack too but the more likely issue is a bad cat. In that case you either have to pay a shop to put a new one in or get a new y pipe that has both cats on it.

If you just call Lucky8 I bet they have everything you need.

 

...thanks for the response CHARLIE_V, in fact when I first got my Disco2, it showed a couple engine misfiring codes that ran for a while until I got them taken care of by replacing spark plugs and cables; those went away since, but the one code about the converter came on a little time after, and remember someone telling me that I needed to change the cat since that misfiring issue might had damaged it ...the other two came about many, many months later; in fact the purge valve's not more than 2 months ago or so... so based on this info, before attempting to repair the cat issue, should I replace or have the O2 sensors checked? which should I be looking into, front, rear or both, driver or passenger side? do you know what are the consequences of driving with a bad cat down in Florida, will it only affect mileage? ...as per the purge valve, yes I've read about that Hyundai part you mentioned ...should I tackle these issues in a particular order if money is an issue? ...thanks again! ;-]#

 

If you drove on a misfire for any amount of time the cat is almost definitely dead.

Definitely replace the O2. No point in testing it, the computer isn't getting any signal at all. Be sure to use genuine Bosch. The cheapies don't work, I've tried.

Consequences would probably be a $40 exhaust ticket. Of course, without emissions testing the chances of anyone knowing is slim to none. I'm also in a state without emissions testing and I removed my cats. Bad gas mileage, down on power, puts a strain on the engine and may eventually lead to misfires or simply not running at all due to excessive backpressure due to the clogged cat.

 

As Alex said, misfires kill cats. What happens is the misfire results in raw gas in the exhaust, which then can eat the catalyst in the cats. Also, unburnt gas in the cats will actually detonate in them. If you've ever seen the inside of a cat it is basically a dry honeycomb. Since all of your exhaust on that side has to pass through it, when the catalyst clogs up with goo or breaks into dust your engine can't push out exhaust and it won't run. On my Titan it has two cats per side. I had a bad spark plug and that destroyed my first cat, which then disintegrated, and the crumbling catalyst blew down and clogged the second one. I couldn't drive over 3 miles an hour when that happened. It sucks.

So the O2 definitely needs to be replaced if it is actually plugged in. It is possible that the connector has gunk in it or is just dangling so check that first. The engine will continue to run badly if the purge valve is bad so I'd also replace that too, and they are cheap.

You might be the luckiest person on the planet and a good running engine might heat up your cat enough to burn off whayever is giving it issue, but I'm afraid you will end up replacing it, too. That's expensive.

Forum wisdom is to replace the O2s in pairs (both left and right front), at least. I'll admit that I have sometimes just replaced the malfunctioning one. Alex's advice to get genuine Bosch O2s is a money saver... If you get other brands they usually fail quickly.