2001 highlander catalytic converts


#1

I was told one of three cat converts is cloged.how do you repair this does it need all 3. I am also having transmission problem with the same what is wrong with this toyota.


#2

Can you tell us how many miles the truck has,
what engine,
what the maintenance history has been,
what the symptoms are that caused you to bring the truck in,
who told you the converter was clogged and what tests they did,
and what symptoms you’re having that you suspect are the tranny?


#3

To say that one of three Catalytic convertor is clogged is a fairly direct statement…what caused this…they dont normally fail this way without some direct incident acting upon them…like an accident or running over something that hit the bottom of your vehicle.

I have only seen one cat fail by being clogged…and this was due to an additive… Can you drive the car? If a cat is clogged the car wouldnt run actually


#4

We get lots of posts on this forum wherein one says “I was told that…” and upon further questioning we find out that it was a buddy or coworker that told them that and the symptoms don’t even fit the guess. I’d be reluctant to make any assumption based only on the information in the original post.

The only clogged cat I’ve seen was due to crumbled ceramic substrate, the honeycomb broke up.

I’m also wondering about the tranny comment. If it’s an automatic and the tranny is slipping, someone’s well-meaning friend might interpret the lack of power as a clogged converter when in fact the problem is a leak in the tranny cooling line…and a dixie cup worth of fluid left. Torque converters don’t work well without fluid. An experienced fella can tell the difference by whether the engine revs or not, but we don;t have enough info here to be making any assumptions.

I maintain that more info here would be a great asset. We really don;t have enough.


#5

104thousand engine 3.0 v6 .to keep truck running when it is cold must keep foot on gas.amcco said cat was cloged.but he couldnt tell me which one. the truck down shifts between 2nd and 3rd gear jerks.we change all spark plugs and 6 coil packs.thay tell the car does not have a misfire any more. Its been to 2 shops ,aamco and Toyota.


#6

Its 3.0 v6 it been to 2 shops , Toyota and aamco. Been tuned up plugs 6 coil packs some wire replace was told it does not have a miss fire any more. car jerks between 2nd and 3rd gear. aamco said cat is cloged 0ne of them couldnt tell which one, also said we need a new tranny. Its driving me nuts.


#7

I have only seen one cat fail by being clogged…and this was due to an additive

And additive…really?? How were you able to determine that??


#8

Are these the only symptoms you’re experiencing?
If you had a plugged cat converter, you’d be struggling to accelerate; power would be poor. The engine would be having difficulty pushing the exhaust out, and if it cannot purge the cylinders of the spent fuel, it cannot refill them with fresh fuel.

Jerking at a single shift point suggests to me a tranny problem. I’m not a tranny guy, so I’ll withhold speculating, but perhaps Transman will stop by or someone else here who’s been inside a number of trannys can join in and post.


#9

When truck is running at a study speed it runs fine, stopping at a light pulling off the truck jerks, when rpms get past 2 jerking starts then it levels out and runs fine.we also have to push on the gas to start the truck. as long as the truck has warmed up it starts, but if it sets long enough to get cold it harder to start. aamco thats because the cat converter is cloged.Help please!!!


#10

Having to step on the gas to get the engine to start is more likely a dirty idle air control valve. Some Toyotas of this vintage had issues with the idle air control valve. Try removing the part and cleaning it with carburetor cleaner to see if that clears the problem up.

If your catalytic converter were clogged up, you would likely experience a lack of power, limited top speed (sometimes as low as 15 mph), and often a check engine light with a code P0402 (plain English translation of “EGR flow excessive” and the cause of parts stores selling a lot of unneeded EGR valves). The only good way to diagnose this will be to have a back pressure test performed. Any shop that does emissions testing will be able to handle this. If you do indeed have a partially clogged catalytic converter, you should fix that before condemning the transmission. A clogged converter can cause symptoms that some may interpret as being a transmission problem.

AAMCO is not a good place to take your car to get any kind of work done, and it troubles me that they seem to be trying to diagnose emissions problems now. Once you determine if you actually need a catalytic converter or not, you need to take your car to a reputable transmission specialist. Chain transmission shops tend to sell everyone a transmission whether they need it or not. There is a running joke amongst mechanics that AAMCO is an acronym for “All Automatics Must Come Out”, and that seems to be their policy.


#11

How was I able to determine that an additive clogged a cat? LOL…pretty easily…the OP used a head gasket additive in their coolant with a cracked head…the additive was spit out the exhaust port into the cat…found the hot spot…and did its job of hardening up like Concrete…It didnt know it was in a cat instead of a cylinder head so it clogged up all the cats honeycomb holes…thats how… Any other questions?

Which is why you disconnect the ex manifolds when you have a bad cyl head or crack and then put in an additive head gasket fix.


#12

I’m glad you answered! That to me is a good sealant side effect to be aware of. We often get posts here asking if these additives work. I’d not seen that happen and would not have been aware of it.