Bad Catalytic Converter?

Tiny
ROBCAL
  • MEMBER
  • 2004 TOYOTA 4RUNNER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 101,000 MILES
Got the ODBII code 0420 indicating a bad catalytic onverter. Everything I have read indicates the 2004 4Runner 6 cyl has 2 catalytic converters. A local reapi shop told me that there are actualy 4. The cat is supposed to be between the 2 oxygen sensors, correct? When I look at the cats to buy online, they are the pipes and parts AFTER the second oxygen sensor. Any advice?
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Tuesday, December 23rd, 2008 AT 2:24 PM

25 Replies

Tiny
ZACKMAN
  • MEMBER
First of all, I would stay away from that local repair shop. Obviously they have not done exhaust work to realize how many cats go to a vehicle.

This video can help us see if the cats are bad

https://youtu.be/kNXh1Lphzr4

You have four catalytic converters, and the one that is giving you trouble is cat#1, the one on the passenger side.


https://www.2carpros.com/forum/automotive_pictures/55316_4runnerheads_1.png



Before you purchase, read this description of the trouble code.

P0420 OBD-II Trouble Code Technical Description

Catalyst System Efficiency Below Threshold (Bank 1)

What does that mean?

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Symptoms

You will likely not notice any drivability problems, although there may be symptoms.

Causes

A code P0420 may mean that one or more of the following has happened:

* Leaded fuel was used where unleaded was called for
* An oxygen sensor is not reading (functioning) properly
* The engine coolant temperature sensor is not working properly
* Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
* Retarded spark timing
* The oxygen sensors in front and behind the converter are reporting too similar of readings

Possible Solutions

Some suggested steps for troubleshooting a P0420 code include:

* Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
* Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
* Inspect the downstream heated oxygen sensor (HO2), replace if necessary
* Replace the catalytic converter

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.

*** I would call Toyota and find out about the extended warranty ***
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+7
Saturday, December 27th, 2008 AT 4:09 AM
Tiny
CARFIX4US
  • MEMBER
  • 2003 TOYOTA 4RUNNER
Interior problem
2003 Toyota 4Runner 6 cyl Automatic 132000 miles

How many catalytic converter in my truck?
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Tuesday, October 20th, 2020 AT 1:16 PM (Merged)
Tiny
DOCFIXIT
  • EXPERT
Two left bank, right bank
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Tuesday, October 20th, 2020 AT 1:16 PM (Merged)
Tiny
CARFIX4US
  • MEMBER
How much for the 2 top ones
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Tuesday, October 20th, 2020 AT 1:17 PM (Merged)
Tiny
DOCFIXIT
  • EXPERT
Run @$900
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Tuesday, October 20th, 2020 AT 1:17 PM (Merged)
Tiny
HELPINGPUPS
  • MEMBER
  • 2000 TOYOTA 4RUNNER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 100,000 MILES
Engine light came on, dealer said "both" California converters on this SUV had gone bad. Vehicle is in Arizona. Took car through emissions 5/6 months later and it passed no problem. One year later engine light came on again. 4 codes 661-Air leak, 662-AF sensor, 663-Fuel system Fault, 664- Faulty Converter. Should I go purchase a new vehicle? Are the converters really bad or is it something else. Dealer said I couldn't put aftermarket converters on a Toyota. Need some help please? Bad economy funds are at a premium.
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Tuesday, October 20th, 2020 AT 1:17 PM (Merged)
Tiny
MHPAUTOS
  • EXPERT
HI there,

You can put after market converters on a Toyota, they just say that to make a sale.O you have the OBD11 codes they will be a P**** code, this will help me with the diagnosis.

Mark (mhpautos)
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Tuesday, October 20th, 2020 AT 1:17 PM (Merged)
Tiny
MVONDOHLEN
  • MEMBER
  • 2000 TOYOTA 4RUNNER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 82,000 MILES
I have had the catalytic converter stolen. Dealer charged 2400. For repairs and tow. Out insurance deductible. Is there some device or manner in which to secure the converter from future thefts?
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Tuesday, October 20th, 2020 AT 1:17 PM (Merged)
Tiny
BLACKOP555
  • EXPERT
A shot gun and a guard dog!

You may be able to have a box made for it that you can put around it. OR you could put an alarm system on it, so if they touch it the system will go off.
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Tuesday, October 20th, 2020 AT 1:17 PM (Merged)
Tiny
JDCURRY04
  • MEMBER
  • 2000 TOYOTA 4RUNNER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 183,000 MILES
I own a california emissions equipped 4runner. I have had the code for failed catalytic converter for a long time with no effects on performance. I just installed aftermarket converters on it and replaced the O2 sensors on the converters. The code then went to fuel mixture too rich. I replaced the MAF 02 sensor and spark plugs (that showed no fouling). Now the code is back to catalytic converter failed. What could this mean?
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
MMPRINCE4000
  • EXPERT
You will most likely have to install the original Toyota convertors, as the aftermarket are not approved for use in CA.

A rich fuel mixture will cause convertor failure. Best approach is to have car scanned in live data mode and compare all sensor values to factory specs. Also check fuel pressure.

Find the rich mixture problem before replacing convertors.
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
CARAWAY
  • MEMBER
  • 1999 TOYOTA 4RUNNER
I have a 1999 Toyota 4 Runner with a mileage of 71,535 miles. Last week, my catalytic converter was sawed off and stolen when my car was parked at a mall. While the Toyota service personnel estimated my bill at 2000, the Meineke people told me it would be about $340 in damages since the sensors were intact and the converter was cut.
What do I go with?
Need an urgent answer, will appreciate your help greatly. Thanks.
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
RASMATAZ
  • EXPERT
Either you go with the original Cat or an aftermarket compatible
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
CARAWAY
  • MEMBER
Pls. Can you elaborate what you mean by aftermarket compatible?
When you say "original cat" do u mean the one which is quoted by Toyota service people?
Thanks a lot for your help and answers.
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
BMRFIXIT
  • EXPERT
What I think he means it’s your money.

If u can find one that’s made to fit your car by spec
For less than what the dealer gave u
Go for it
Do not go for a universal one or u will have a catalyst codes
Good luck
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
SUSAN4RUNNER
  • MEMBER
  • 1999 TOYOTA 4RUNNER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 169,300 MILES
I brought my 4Runner in for a check this morning becuase I am seeing transmission fluid leaking in my garage. The check engine light also came on over the weekend. I was told by my mechanic that they cannot find any leak and all fluids are full. As for the check engine light, I am being told my front & rear catalytic converters need to be replaced and will cost $2,800. This seems outrageous to me, but maybe it isn't. It does seem to have alittle chugging when started first thing, but overall appears to be performing well. Can you advise me on this? Thansk so much!
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
BLUELIGHTNIN6
  • EXPERT
Do you know what codes you got from the engine light? Cat. Converters are extremely expensive so the quote you got is a fair price. It is the parts that is so expensive not the labor.

Thanks for using 2CarPros. Com !
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
ROBERT.HERNANDEZ
  • MEMBER
  • 1997 TOYOTA 4RUNNER
  • 6 CYL
  • 4WD
  • MANUAL
  • 230,000 MILES
What is the cost to install a catalytic converter for a 1997 Toyota, 4-Runner SR5. It is a manual 5 speed 6 cylinder engine?
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
DOCHAGERTY
  • EXPERT
I suppose that would depend on who you would call to quote on the job, anywhere from 200 bucks on up for the cat, maybe about the same for labor to install. There are a lot of variables in this equation mate. Good luck.
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)
Tiny
MISSY111063
  • MEMBER
  • 1997 TOYOTA 4RUNNER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 240,000 MILES
How do I change the engine code to run without a catalytic converter?
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Tuesday, October 20th, 2020 AT 1:18 PM (Merged)

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