Question about 2000 Toyota 4Runner
REPLACED O2 SENSOR REPLACED AIR/FUEL SENSOR PUT 92 OCTANE WITH CLEANER ADDITIVES FOR INJECTORS ETC. LIGHT STILL COMES ON AFTER COUPLE DAYS 0420 PENDING LIGHT & 0420 LIGHT AFTER FEW DAYS ARE CATS THE PROBLEM OR IS THERE ANYTHING ELSE TO CHECK.
DTC P0420 - Catalyst System Efficiency Below Threshold (Bank 1)
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.
You will likely not notice any drivability problems, although there may be symptoms.
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
******** spark timing
The oxygen sensors in front and behind the converter are reporting too similar of readings
Some suggested steps for troubleshooting a P0420 error 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.
Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.
Thank you for using FixYa, have a nice day.
Posted on Feb 17, 2012
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Hello and welcome to FixYa!
Yes indeed. It can be a bad coil. This is common on this car specially if the check engine light doesn't go off after the O2 replacement. Have it replaced and I believe you'll be good.
Hope this helps and thank you for using FixYa! Have a good one!
Posted on May 21, 2011
SOURCE: using more rpm to maintain
If the RPM is higher at any particular speed than before, the only cause could be that the transmission is slipping. Things like O2 sensors, Catalytic converters, fuel treatments, etc. have absolutely nothing to do with incresed engine (input) speed to axle (output) speed ratios.
Posted on Aug 06, 2011
Tips for a great answer:
Jan 15, 2016 | Cars & Trucks
Oct 14, 2014 | Cars & Trucks
Jan 03, 2013 | 2000 Toyota Tacoma PreRunner
Dec 10, 2010 | 1997 Honda Passport
Jul 29, 2010 | Buick Rendezvous Cars & Trucks
Jan 02, 2010 | 1999 Lexus RX 300
Oct 09, 2009 | 2001 Lexus RX 300
Jul 30, 2009 | 2000 Ford Taurus
Jun 25, 2009 | 2003 Chevrolet TrailBlazer
647 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: