# 2011 2.5L 4Cyl Rav4 P0420 - At a loss for ideas **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** catalytic-converters, rav4, toyota\ **Created:** [October 13, 2023, 1:15am UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353 "2023-10-13T01:15:21Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![nofyfb\_180405](https://avatars.discourse-cdn.com/v4/letter/n/22d042/32.png) [@nofyfb\_180405](https://community.cartalk.com/u/nofyfb_180405)\ **Post date:** [November 8, 2023, 10:50pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/21 "2023-11-08T22:50:57Z")
Sorry - as soon as I saw “rockauto”, I was immediately thrown off. I only order OEM parts that are time-consuming to replace. That includes AC stuff. Granted, I only have/work on Toyotas so Denso is usually the main choice. For light/small stuff, there is a site in Dubai that sells parts for about 30% of US price with shipping faster than from alabama. Unfortunately, shipping may be expensive for larger parts. Again, in the US, Denso is the best source. ---
**Author:** ![bcohen2010](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@bcohen2010](https://community.cartalk.com/u/bcohen2010)\ **Post date:** [November 9, 2023, 3:29am UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/22 "2023-11-09T03:29:59Z")
RockAuto is for DIYers, not professional mechanics. And as a DIYer, I shop there. I have had very few issues with parts purchased there, mainly shipping damage, but I also only buy brand-name parts, not generic-branded. I have never bothered trying to return anything to them, so I cannot comment on their return policy. The last time I got a damaged part from them, it was a head gasket, which got bent by other heavier parts in the box. It was not worth the risk of using, so I threw it away and bought another one from a different vendor to complete the repairs. Tell me more about the warranty policy for an A/C compressor, because I actually need to replace the compressor in my 2004 Corolla, and I was planning to buy the new compressor (and possibly other parts) from RockAuto. The existing compressor runs, but does not pump properly, and there is no evidence that the bearings came apart, which would necessitate replacing the condenser, etc, though I may do so simply to satisfy warranty requirements. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [November 9, 2023, 3:36am UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/23 "2023-11-09T03:36:41Z")
Never had a problem returning stuff to RockAuto. Let them know there’s a problem with the order, and they send everything required to return it. Except. you have to drop the return package off at a FedEx store. Tester ---
**Author:** ![eddo](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/eddo/32/2594_2.png) [@eddo](https://community.cartalk.com/u/eddo)\ **Post date:** [November 9, 2023, 11:39pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/24 "2023-11-09T23:39:21Z")
> [@wildlight](#): > > If the issue is that it is a bad converter then I have been very much ripped off by my mechanic… If your mechanic has been the one blindly tossing all these parts at your vehicle instead of actually diagnosing it- then yes: you are being ripped off. ---
**Author:** ![wildlight](https://avatars.discourse-cdn.com/v4/letter/w/c5a1d2/32.png) [@wildlight](https://community.cartalk.com/u/wildlight)\ **Post date:** [November 10, 2023, 5:42pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/25 "2023-11-10T17:42:23Z")
Hello my friends, Sorry for disappearing, I started up a new placement at the hospital and its been extremely hectic. Since my last post, I’ve gone through a few different things and some new things have arisen as well. As suggested I did replace the o2 sensor & A/F sensor with denso ones, since regardless of the likely converter issue I felt it would be best to move forward with those. Now, as for the other issues, such as the mechanic charging me an insane amount for a part that is both incorrect for my car and does not work, I went and talked to them about it and they were basically like “We can see what we can do.” This was a few weeks ago, and they’ve been dipping and dodging me ever since then, so I really think I am just out the money and that’s that on that. In terms of exhaust leaks, the car has recently developed a significant exhaust leak at the manifold gasket and the front pipe. I took it to a local muffler shop and they quoted me $4500, which is an insane amount and I am not going to pay that. They told me this is because I need a new manifold (likely), a new front pipe, and a new second catalytic converter. The prices however, are excessive and I think they may have given me that large of an amount because they just don’t want to do the job. The problem now is my car fills up with exhaust fumes whenever I run the AC (not on recirculate) and the gas mileage has gone into the toilet, which I assume is due to the leak at the manifold messing with the A/F sensor. I think I’m going to have to go to another town to get this fixed for a reasonable price since this is beyond my scope of abilities and the places here either offer insane prices or just don’t want to do it. With regard to the o2 sensor data that was requested, I can pull up these graphs on my OBDII scanner and post them here later. The (original) motivation for solving the problem is that although it’s not required to re-register (at this time), they are doing “random” roadside checks on cars at the truck inspection stations outside my town periodically (they flag you down and you have to go for a spot check) and if you fail they take your licence plates until you fix whatever they tell you needs to be fixed. Now my motivation is also that I don’t want to get carbon monoxide poisoning from the leaks. Thanks everyone for your input. ---
**Author:** ![bcohen2010](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@bcohen2010](https://community.cartalk.com/u/bcohen2010)\ **Post date:** [November 11, 2023, 3:25am UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/26 "2023-11-11T03:25:43Z")
Your car is filling up with exhaust fumes, and you are worried that the repair costs are too high??? Look, I am as cheap as the day is long, but come on, this is a matter of health and safety. And it’s not just _your_ health and safety. If you pass out, and cause a serious accident, this affects the other driver’s health and safety as well. At some point, you either need to pony up and fix this vehicle, or sell/trade it in, and buy something else. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [November 11, 2023, 5:06am UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/27 "2023-11-11T05:06:25Z")
> [@wildlight](#): > > the car has recently developed a significant exhaust leak at the manifold gasket That is the cause of the catalyst efficiency fault, a very small exhaust leak near the catalytic converter or an oxygen sensor can cause a P0420 fault. Now that the leak has worsen, you have become aware of the leak. What caused the manifold/catalyst assembly leak? The manifold flange may have been flawed or the manifold was damaged/warped during installation. It sounds like you have been unable to get the repair shop to take responsibility for the failure. There is a notion around here that independent repair shops are the best. > [@wildlight](#): > > With regard to the o2 sensor data that was requested, I can pull up these graphs on my OBDII scanner and post them here later. Unnecessary; there is an exhaust leak. ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [November 11, 2023, 2:32pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/28 "2023-11-11T14:32:28Z")
> [@Nevada\_545](#): > > What caused the manifold/catalyst assembly leak? The manifold flange may have been flawed or the manifold was damaged/warped during installation. Most likely it was the high quality of the Excel Exhaust Manifold Converter for $158.00 that was installed… 🤦‍♂️ 😁 ---
**Author:** ![wildlight](https://avatars.discourse-cdn.com/v4/letter/w/c5a1d2/32.png) [@wildlight](https://community.cartalk.com/u/wildlight)\ **Post date:** [November 11, 2023, 6:25pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/29 "2023-11-11T18:25:31Z")
The cause is unknown other than I’ve been told by both places I’ve gone that its occurring at the manifold gasket. Also davesmopar said, if I had to attribute it to anything it is probably that the manifold is poorly built and if they’re okay with using that bad of a manifold I assume they would also use poor quality gaskets. A learning experience indeed… a very expensive one. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [November 12, 2023, 10:39pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/30 "2023-11-12T22:39:36Z")
I concur w/Nevada’s assessment above. Best course is to first correct all the exhaust leaks. That may resolve the other problems entirely. On modern fuel injected engines using O2 sensor feedback to calculate the air/fuel ratio, there can be no leaks in either the intake air or exhaust system. All of the air that comes in, plus the amount of fuel injected must exactly match the amount of everything that that leaves through the exhaust pipe. Any leaks will confuse the computer to no end. ---
**Author:** ![wildlight](https://avatars.discourse-cdn.com/v4/letter/w/c5a1d2/32.png) [@wildlight](https://community.cartalk.com/u/wildlight)\ **Post date:** [November 16, 2023, 7:57pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/31 "2023-11-16T19:57:13Z")
All has become clear. In keeping with the suggestions here, i have repaired the exhaust leaks. Got it for $650. Second cat had to be replaced. Interestingly, the reason for this failure is because the high quality excel exhaust catalytic converter completely fell apart and was empty. It is not immediately clear why, I’m not burning oil or losing coolant, but I spoke with the shop that installed the manifold and supposedly this is warranty covered. Given that the manifold converter is literally empty, it makes sense I was still getting a p0420. The plugged second converter also explains other issues. Will update you guys on what the final ending is to this gripping story. Attached are images of the empty manifold and the plugged second cat. ![IMG_0655](https://global.discourse-cdn.com/cartalk/original/3X/0/3/030ff913d70672ce913fa753ec786de3c4e2eee6.jpeg) ![IMG_0654](https://global.discourse-cdn.com/cartalk/original/3X/b/5/b5769b2aec42fa7ffe83031c1b3567d21fff60f9.jpeg) ![IMG_0653](https://global.discourse-cdn.com/cartalk/original/3X/b/8/b8572e59a192ee95f56ec75bb07a3f2170bcb290.jpeg) ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [November 16, 2023, 8:15pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/32 "2023-11-16T20:15:54Z")
> [@wildlight](#): > > catalytic converter completely fell apart and was empty. It seems like something like that could happen. The cat’s guts is just a block of of ceramic material. Ceramic is inflexible, has a tendency to crack and break apart, like what happens when a ceramic dinner plate accidentally falls on the floor. The debris from the cat would usually end up in the muffler. Sometimes car owners will purposely knock the ceramic out of the cat as well. (Don’t do this, illegal, big fine possible, and won’t pass emissions testing.) If you purchased a used car, that’s another possibility. > [@wildlight](#): > > Given that the manifold is literally empty, it makes sense I was still getting a p0420. The exhaust manifold is supposed to be empty. Presuming you mean the cat is empty , the insides of which can be seen with the cat disconnected from the exhaust manifold. Or is the exhaust manifold and the cat the same part? Emissions components (like cats) are often warranted for 8-10 years, federal requirement. Not sure about a 12 year old car like yours though. Are the symptoms totally resolved now? If so, good for you 🙂 ---
**Author:** ![wildlight](https://avatars.discourse-cdn.com/v4/letter/w/c5a1d2/32.png) [@wildlight](https://community.cartalk.com/u/wildlight)\ **Post date:** [November 16, 2023, 8:17pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/33 "2023-11-16T20:17:45Z")
The manifold had an integrated catalytic converter. Currently there is no ceramic there due to it having blown apart and subsequently being empty. Gonna get it replaced (theoretically under warranty) because it was installed in May. The debris from it are what blocked up the second cat, and since the back of the second cat is (was) still intact it’s unlikely much got into the muffler. Still getting P0420 but I expected that, the car definitely runs better now though. I guess i got used to poor performance and didn’t really notice it. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [November 16, 2023, 8:28pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/34 "2023-11-16T20:28:45Z")
Ok, I think I’m finally getting the picture. The exhaust manifold was recently replaced, then ceramic matrix inside the replacement exhaust manifold crumbled and ended up in the second cat, blocking free exhaust flow. The second cat has now been replaced, and the car performs much better even though the exhaust manifold still has no guts, and needs to be replaced (hopefully under warranty) with a new one, explaining the continuing p0420. The only thing still unexplained is what caused the replacement exhaust manifold’s ceramic matrix to crumble? I’m guessing it was a manufacturing defect, faulty part when installed. ---
**Author:** ![wildlight](https://avatars.discourse-cdn.com/v4/letter/w/c5a1d2/32.png) [@wildlight](https://community.cartalk.com/u/wildlight)\ **Post date:** [November 16, 2023, 8:41pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/35 "2023-11-16T20:41:50Z")
Yea you have the picture now. 🙂 I’m hung up too on why it would have fallen apart, I am leaning toward it was defective but am willing to consider other causes. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [November 16, 2023, 8:48pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/36 "2023-11-16T20:48:10Z")
hmmm … If the exhaust gasses were overly-hot. The most likely causes - air/fuel mixture is too lean - egr system not working correctly ---
**Author:** ![wildlight](https://avatars.discourse-cdn.com/v4/letter/w/c5a1d2/32.png) [@wildlight](https://community.cartalk.com/u/wildlight)\ **Post date:** [November 16, 2023, 8:49pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/37 "2023-11-16T20:49:35Z")
Wouldn’t those cause a code? If they rose to a sufficient level to blow apart the substrate? ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [November 16, 2023, 8:54pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/38 "2023-11-16T20:54:17Z")
On my own corolla , if the EGR valve isn’t opening when it should, that will cause a code. I expect the same applies to your car. It monitors a temp sensor in the EGR passage, which should get hotter when the EGR valve opens. And yes, overly lean would usually produce a diagnostic code. That can be usually be easily measured w/a scan tool, from the fuel trim data. The exhaust manifold temp can be measured directly of course, but you’d have to have something to compare it to to know if it was too hot or not hot enough. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [November 16, 2023, 8:55pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/39 "2023-11-16T20:55:41Z")
Engine problems will cause the check engine light to illuminate before damage to the catalyst occurs. It was an inexpensive replacement catalytic converter, and someone may have dropped it. How it got damaged isn’t important, there is a warranty. ---
**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\ **Post date:** [November 16, 2023, 9:02pm UTC](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353/40 "2023-11-16T21:02:17Z")
Just hope you are not warranting a junk Cat with another junk Cat… I would get my money back on the 1st junk manifold cat and upgrade to a qualify manifold cat… [Previous page](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353.md?page=1) [Next page](https://community.cartalk.com/t/2011-2-5l-4cyl-rav4-p0420-at-a-loss-for-ideas/193353.md?page=3)