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05GXowner

Codes P0420 And P0430 Troubles - Need Help

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Hi, we've had a 2005 GX470 with 83,000 miles since 2007. Recently, the dashboard lights have all been coming on temporarily then going off before we could get it to the dealer. We finally made it in and their (Lexus dealership) diagnostics read a "P0420 and P0430 failure with AF sensors, O2 sensors, and catalyst system efficiency below threshold (Bank 1) (Bank 2)". They, of course, recommended replacing all sensors and convertors at an estimated cost of $3869.13 - before labor and tax! They incidentally identified a small leak in the radiator and again recommended replacing with an estimated cost of $1179.21 before labor and tax. They gave my wife a quote of $6500, which she admits almost made her cry considering she went in for an oil change. I'm not much of a mechanic but this seems like a typical dealership !Removed!.

Question 1. Any suggestions on where to go to have someone other than the dealership (i.e., national chains) check the exhaust and confirm that these sensors and cats need replaced? Also, woudl you recommend using someone other than the dealer to do jobs like these? I read a conversation on this board (Man777 I think) about using either Toyota parts or other aftermarket parts to replace at a cheaper cost. Any suggestions as we do plan to keep the vehicle for a good while?

Question 2. I assumed that most radiator leaks could be fixed rather than require they be replaced entirely? Any suggestions on who, besides the dealer, could fix the radiator if indeed it can be fixed rather than replaced?

Thanks in advance for any help.

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Hi, we've had a 2005 GX470 with 83,000 miles since 2007. Recently, the dashboard lights have all been coming on temporarily then going off before we could get it to the dealer. We finally made it in and their (Lexus dealership) diagnostics read a "P0420 and P0430 failure with AF sensors, O2 sensors, and catalyst system efficiency below threshold (Bank 1) (Bank 2)". They, of course, recommended replacing all sensors and convertors at an estimated cost of $3869.13 - before labor and tax! They incidentally identified a small leak in the radiator and again recommended replacing with an estimated cost of $1179.21 before labor and tax. They gave my wife a quote of $6500, which she admits almost made her cry considering she went in for an oil change. I'm not much of a mechanic but this seems like a typical dealership !Removed!.

Question 1. Any suggestions on where to go to have someone other than the dealership (i.e., national chains) check the exhaust and confirm that these sensors and cats need replaced? Also, woudl you recommend using someone other than the dealer to do jobs like these? I read a conversation on this board (Man777 I think) about using either Toyota parts or other aftermarket parts to replace at a cheaper cost. Any suggestions as we do plan to keep the vehicle for a good while?

Question 2. I assumed that most radiator leaks could be fixed rather than require they be replaced entirely? Any suggestions on who, besides the dealer, could fix the radiator if indeed it can be fixed rather than replaced?

Thanks in advance for any help.

If you plan to keep the vehicle for awhile, I would suggest keeping the services at your Lexus dealer. I took the bite at a $2800 bill last month for the 60k check up and the timing belt. It's worth it because I would never trust the outside shops to service a $50k vehicle like this. This car has too many sensors and computers that outside shops may not be familiar with.

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I know this is an old topic, but I felt compelled to reply since I was doing my own research and this thread came up. I'm surprised no one else commented on this.

I'm not a great mechanic. I'm an internet mechanic. Besides oil changes, brakes jobs, suspension modifications, I've talked a couple of bigger jobs (with some help) such as an engine install in a Toyota Camry, intake manifold gasket repair on my Chevrolet suburban, Fuel pump on my suburban. All done with research online, and in some cases, ordering the factory manual on CD from ebay.

I've replaced 02 sensors on my wife's Lexus. The quote here is highway robbery. Most of the 02 sensors are all the same. The 02 sensors are around $100 a piece. Denso non-OEM sensors are around $60 a piece, but may require wire splicing. I've replaced one 02 sensor, and I am about to replace another. Before replacing the whole catalytic converter system, I'd first replace the bad 02 sensors. And more importantly, I would target only the bad ones that come up on the code reader. I bought a $30 USB code reader from Amazon and use my laptop for diagnostics.

A radiator repair/replacement should not cost over $1000. Worst case, source the parts online, and pay an independant shop to do it.

I use this source for OEM parts.

http://www.trademotion.com/partlocator/index.cfm?siteid=214915

Again, not really wanting to bring a topic back up from the thread, but I figure this might help someone in the future.

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If you plan to keep the vehicle for awhile, I would suggest keeping the services at your Lexus dealer. I took the bite at a $2800 bill last month for the 60k check up and the timing belt. It's worth it because I would never trust the outside shops to service a $50k vehicle like this. This car has too many sensors and computers that outside shops may not be familiar with.

Dens...I am really surprised after you have mentioned that to stick with the dealer, look here you have quoted $2800 for a 60K check up job, and replacement of timing belt, Even the manufacturer does not suggest to replace at 60K, so the dealer has ripped you to do this job so early, unlike a 90k job wherein the timing belt are replaced.

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