Hyundai Forums banner

2007 Entourage P0420 error code - catalyst bank 1 efficiency threshold

7K views 6 replies 5 participants last post by  chagmaier 
#1 ·
Hello everyone,

This is my first post after a month or so of reviewing forum posts on this issue. I'm at my wits end with this issue.

I have changed both bank 1 and bank 2 downstream O2 sensors since bank 2 side 2 (front of engine) was throwing an error code and a wire was rotted on sensor. I have a VAGCOM software and cable package when I owned several VW's and did a realtime mapping of all O2 sensors. Every one of them seem to be operating and are not stuck on 1.275V (indicates short or open) when engine was at operating temperature. Bank 2 Side 2 exhibited this problem.

I now have this issue, but not have ruled out any other cause. After reading several other posts, a diagnosis of a bad catalytic converter, hole in exhaust between sensors, vacuum leak in Ho2 hoses, etc have not been ruled out.

I would like to ask all of you forum members for assistance and figure out what is next likely area to investigate.
 

Attachments

See less See more
1
#2 ·
If you monitor the O2 voltage for both sensors on the bank, what you want to see is after driving at a constant speed for a few miles the second O2 will run just below the average high voltage of the first O2. So if you see the first O2 peak around .750v say, then the second O2 when in closed loop and constant throttle should be around .700vs, but not oscillate like the first.

If the two O2s are mimicking each other then the cat is not doing anything.
 
#3 ·
I had this code on the new-to-me 07 after replacing the engine. During the swap I noticed that the shielded flex pipe between the front bank pipe and the rear pipe was too limp and probably leaking.

A bad flex pipe will allow ambient air to be sucked into the exhaust system and the extra O2 will throw off the downstream O2 sensor.

I bought a new front pipe assembly (Hyundai calls it a "muffler", p/n 28610-4D100) and installed it a couple of weekends ago. Code has not returned.

We see P0420 a lot at work and always look for a bad flex pipe. A local exhaust shop can weld in a new pre-fab flex pipe section and it's a lot cheaper that buying the whole pipe ("muffler") assembly. Not as neat a job, though, and I wanted something that will last as long as I own this van.

Pics tomorrow if I can manage it.
 
#7 ·
Sorry to resurrect a dead post, but this post seems to be the light at the end of my tunnel. I have an 07 entourage that has had the p0420 code for the last 3 years. I have avoided the high cat replacement costs. However the fuel mileage is getting me in the pocket and I'd like to get this fixed.

My findings show B1S1 operating similar to B2S1. B1S2 shows random dips to .125mV, while B2S2 is running .750 to .6xxmV. I have found that my Y pipe leaks at the same flex joint as yours. With a cold exhaust, I sprayed soap on both flex couplings and started the engine to find it. I have temporarily wrapped aluminium tape around the leaking flex joint to seal the leak and have another look at my HO2 sensors.

My leak is on the larger flex coupling on the downstream end. If this were the actual cause of the P0420, how does it only effect bank 1? I have not yet looked at fuel trim to rule out top side issues, but I'd like to justify doing a repair on the leaking Y pipe. Have you ever seen this effect bank 2 (P0430)?
 
#4 ·
Remove the plastic flex piping between airfilter and engine intake.

Look at it really closely, use you hands to check for small cracks that will allow extra air flow.

This happened on brothers entourage causing multiple o2 codes. Hyundai uses good o2 sensors and they normally last.
 
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