Toyota FJ Cruiser Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
54 Posts
Discussion Starter #1
Have replaced spark plugs, MAF, o2 sensors. Still have all dash lights illuminated with codes p0420 and 0430 I guess running on dead alternator ruined catalytics

Looking for suggestions on aftermarket to get things running right again with no dash lights
 

·
Registered
Joined
·
728 Posts
Have replaced spark plugs, MAF, o2 sensors. Still have all dash lights illuminated with codes p0420 and 0430 I guess running on dead alternator ruined catalytics

Looking for suggestions on aftermarket to get things running right again with no dash lights
Sorry for your troubles, have you cleared the codes and if so how long before they return?

Im sure you have seen this, ALL CREDIT to FJAMMING for the best post ever on this subject! See HIS comments below


I'm reposting the info on OBD-II Trouble Codes - OBD-II DTC Trouble Codes Repair Help Site:
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.



This is for p0430.

Catalyst System Efficiency Below Threshold (Bank 2)
What does that mean?

Basically this means that the oxygen sensor downstream of the catalytic converter on bank 2 is detecting that the converter 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 such as a rough/hard idle when cold.
Causes

A code P0430 may mean that one or more of the following has happened:

* The catalytic converter is no longer functioning properly
* An oxygen sensor is not reading (functioning) properly
* There is an exhaust leak

Possible Solutions

First, inspect for exhaust leaks.

Next step is to measure the voltage at the oxygen sensor on Bank 2. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.

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 Have a V-8!! Moderator
Joined
·
28,837 Posts
Make sure which one or ones are bad if any since there are 4 of them. The 2 primary cats are part of the exhaust manifolds and then the two "muffler" looking type are the secondary ones.
 

·
Premium Member
Joined
·
1,676 Posts
Just get O2 simulators and screw the bad cats or if you're determined to replace the cats get a O2 simulator to see if the code clears. This way you know it's the cats and sell the simulator after replacement.
 

·
Registered
Joined
·
1,205 Posts

·
Registered
Joined
·
195 Posts
Diagnosing a P0420 is one of the hardest codes to repair. You have already thrown a lot of money at it. I truly suggest watching these 2 videos, getting a code reader capable of reading fuel trims and doing a little research. Borpa11 has a great post above and I will use that to help me find the problem with my Miata that has thrown this code as well. This guy is truly amazing at teaching. Watch parts 1 and 2.
 

·
Registered
Joined
·
54 Posts
Discussion Starter #10
To end the saga it turns out new manifold cats were required up front both sides. Went with magnaflo California approved, all is well now
 

·
Registered
Joined
·
505 Posts
To end the saga it turns out new manifold cats were required up front both sides. Went with magnaflo California approved, all is well now
Since you used Magnaflow does it run better?
Can you post photos of them installed?

Thanks George
 

·
Registered
Joined
·
120 Posts
Dragging this thread back to life since I just ordered the MF manifold/cats. I don't have codes showing but all my exhaust hardware is completely and totally rusted to crap. I'll post pictures of the install since ssbmiken got what he wanted and now doesn't care about the rest of us...! I got the best price off of amazon. I'll have to figure out something for the rest of the exhaust system when I get my cabbage grabbers on the new manifolds.
 

·
Registered
Joined
·
33 Posts
So... I had a persistent misfire. took FOREVER to diagnose. After 14 months I found an intake valve leak on cylinder 1. So after the engine was swapped (under aftermarket warranty) I started getting a p0420 code .. I knew the catalytic had an issue due to the yr of unburned particulates.. but $2613.38 for a full set of new ones or $1246.22 for that side wasn't going to happen.. So I turned to YouTube (which I hate to admit too, as there's ALOT OF BAD ADVICE out there). But doin some research I found a vid that actually made sense... since the motor's less than 2 months old there's no need to clean it. but there's a way to clean out the cats... remove the top (or front) O2 sensors an spray Seafoam directly on to the catalytic converter (I did both sides for good measure) so half a can per side. replace the O2 sensors an let it sit about 30mins.. ( a word of advice DO THIS OUTSIDE!!) Start the truck an let it run til the white smoke is gone... took about 30mins to get clear (I wound up driving around my neighborhood in low gear for about 10mins to speed up the process 2k rpm range) So far I haven't had the code reappear.. so $17 of Seafoam (they didn't sell the spray separately so I bought the combo pack) cured my catalytic..... hope this helps...
 

·
Registered
Joined
·
1,205 Posts
1 - 15 of 15 Posts
Top