p0430 catalytic or o2 sensor

[nineball481]

I'm getting a p0430 code.
alldata says to replace the cat, so does autozone. I have about 150k miles on original parts (exhaust and sensors)

Autozone had a checklist including:
bad cats, engine misfire, vacuum leak, oil leak into exhaust.

I have had reduced performance recently... sluggish reaction on acceleration, but no misfires. I'm not leaking or burning oil, I'm not sure about a vacuum leak.

Do you believe the cause is the sensor or the cat? Should I replace both?

I read through some of the previous posts, but did not find enough info. thanks for the help.

[old_master]

DTC's NEVER say to replace a part, they tell you what area a problem was detected in. P0430 indicates that the catalytic converter efficiency is low. This can be caused by any one or more of several things. It must be diagnosed properly before replacing any parts, unless money is not an object, in which case, start throwing parts at it, you might fix it, eventually

When the ECM checks for catalyst efficiency, it relys heavily on oxygen sensor data, (especially the sensor after the catalyst) but it also relys on things that can affect oxygen sensor data output too. If a sensor supplies incorrect data, converter efficiency DTC's can be set. The most common causes are poor electrical connections, exhaust leaks, faulty oxygen sensors, and a faulty catalyst. Those are the basics to check first.

[j cAT]

this code is usually the converter.

since you have 150,ooomi on this vehicle replace all 4 O2 sensors. these are only good for about 100,ooomi. this is not my opinion but that of the manufactures.

reset the pcm and see if you get a repeat.

the reason this has occured is usually from the cat converter getting damaged from improper fuel ratios or excessive oil carbon etc.

the other item would be coolant being burned.

point I am making IS do not replace converter until you are quite sure that engine has no issues that WILL create another cat failure.

whenever replacing these converters the upstream O2 sensors should be replaced.................

[777stickman]

Another tip for trouble shooting is to swap both downstream o2 sensors, clear the code and see what happens.

[danielsatur]

The HO2 sensor signal told the ECU, that your catalytic converter on bank 2 is
blown out.
Lightly tap on bank 1 catalytic converter ,and compare the sound with bank 2 cat.
http://www.catalyticconverterwarehouse.com

[nineball481]

thanks for the tips everyone. I will repost later with the final outcome/solution for my problem.

[MAD King]

Hello,

I have a question.

I think I need a new catatytic converter, but all I have found have this note

Not legal for sale on vehicles licensed in the state of California.

Where can I find one which is for California?

[MT-2500]

Originally Posted by MAD King

Hello,

I have a question.

I think I need a new catatytic converter, but all I have found have this note



Where can I find one which is for California?

Best to start a new/thread - post on yours.

But first make sure you need a cat.

[MT-2500]

Originally Posted by nineball481

I'm getting a p0430 code.
alldata says to replace the cat, so does autozone. I have about 150k miles on original parts (exhaust and sensors)

Autozone had a checklist including:
bad cats, engine misfire, vacuum leak, oil leak into exhaust.

I have had reduced performance recently... sluggish reaction on acceleration, but no misfires. I'm not leaking or burning oil, I'm not sure about a vacuum leak.

Do you believe the cause is the sensor or the cat? Should I replace both?

I read through some of the previous posts, but did not find enough info. thanks for the help.

As Old master said code does not say replace the part.

http://www.troublecodes.net/articles/catfailure/

DTC P0420, P0421, and P0430 & P0431: Check Possible Cause Of Misfire DTC P0420 and P0421 indicate bank one catalyst system efficiency is minimum requirement. DTC P0430 and P0430 indicate bank 2-catalyst system efficiency is minimum requirement. Possible causes are as follows: Use of leaded fuel. Oil contamination. Cylinder misfire. Fuel pressure too high. HO2S sensor improperly connected. Damaged exhaust system component. Faulty ECT sensor. Faulty HO2S. Ensure ignition timing is correct. Retrieve all Continuous Memory DTCs. If misfire code is not present, go to next step. If misfire code is present, isolate cylinder and repair as necessary. Check HO2S Monitor DTCs If DTCs P0136, P0138, P0140, P0141, P0156, P0158, P0160, or P0161 were present in step 1), service as necessary before continuing. If none of these codes are present in step 1), go to next step. Check ECT Sensor DTCs If DTCs P0117, P0118, P0125 or P1117 were present in step 1), service as necessary before continuing. If none of these codes are present in step 1), go to next step. If any codes except P0420, P0421, P0430 and/or P0430 were present in step 1), service as necessary before continuing. If no codes except P0420 and/or P0430 were present in step 1), go to next step. Check Rear HO2S Wiring Harness Turn ignition off. Ensure HO2S wiring harness is correctly routed and connectors are tight. Repair or replace as necessary. If wiring harness and connectors are okay, go to next step. Check Fuel Pressure Turn ignition off. Release fuel pressure. Install fuel pressure gauge. Start engine and allow to idle. Note fuel pressure gauge reading. Increase engine speed to 2500 RPM and maintain for one minute. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to CIRCUIT TEST HC. Check For Exhaust System Leaks If exhaust system leaks, it may cause catalyst monitor efficiency test to fail. Inspect exhaust system for cracks, loose connections or punctures. Repair or replace as necessary. If exhaust system is okay, go to next step. Check For Exhaust System Restrictions Inspect exhaust system for collapsed areas, dents or excessive bending. Repair or replace as necessary. If exhaust system is okay, go to next step. Check Manifold Vacuum Install tachometer. Connect vacuum gauge to intake manifold vacuum source. Start engine and raise engine speed to 2000 RPM. Manifold vacuum should rise to more than 16 in. Hg. If manifold vacuum is okay, go to next step. If manifold vacuum is low, go to step 11). Leave tachometer and vacuum gauge connected. Start engine and raise engine speed to 2000 RPM. On a non- restricted system, manifold vacuum should quickly rise to normal range as increased RPM is maintained. On a restricted system, manifold vacuum will slowly rise to normal range as increased RPM is maintained. If manifold vacuum is okay, no indication of exhaust leak or restriction has been detected and testing is complete. If manifold vacuum is low or slow to respond, go to next step. Leave tachometer and vacuum gauge connected. Remove exhaust pipe from exhaust manifold. Start engine and raise engine speed to 2000 RPM. If manifold vacuum is now okay, fault is downstream from exhaust manifold. Reconnect exhaust pipe to exhaust manifold and go to next step. If manifold vacuum is still low or slow to respond, fault is in exhaust manifold or intake manifold gasket. Repair or replace as necessary and repeat QUICK TEST. Leave tachometer and vacuum gauge connected. Disconnect muffler/tailpipe assembly from rear of catalytic converter. Start engine and raise engine speed to 2000 RPM. If manifold vacuum is now okay, fault is in muffler/tailpipe assembly. Repair or replace as necessary and test-drive vehicle to verify elimination of symptom. If manifold vacuum is still not okay, fault is in catalytic converter. Repair or replace as necessary. Check tailpipe/muffler assembly for debris from catalytic converter. Test drive vehicle to verify elimination of symptom.

[MAD King]

Originally Posted by MT-2500

Best to start a new/thread - post on yours.

But first make sure you need a cat.

Thank you. I will.

[nineball481]

thanks, I'm quite aware that the code does not say buy part A or B. Like I posted earlier, Alldata and Autozone both recommend that the converter is bad, while Autozone also suggests that the problem may lie with engine misfire, vacuum leak, or oil leak into the exhaust.
I am just asking for an opinion as to what I should look at fixing first. As I understand, many times the sensor could be the culprit itself. I appreciate any further help that can be offered.

[danielsatur]

Because of Age + mileage consider -
1) Compression test on each cylinder.
2) New plugs.
3) Smoke test for unmetered air leaks.
4) New Air, and fuel filter.
5) Clean MAF, or MAP sensor with CRC MAF sensor cleaner.
6) New upstream H02 sensors only.
7) Catalytic converters canbe check at any local muffler shop.

A poor performance engine could make a good cat go bad, do a little routine maintenance on your
engine 1st.

[maxwedge]

One way to test cat efficiency is to check the inlet temps vs the outlet temps, the difference should be at least 100 degress higher on the outlet with a well warmed up driven engine.

[j cAT]

this may seem weird but try this to check for cat condition. start cold engine , crawl under vehicle and place one hand on each converter if they heat up at the same rate/time the converters are good. if the passenger side takes longer , this then would indicate that the p0430 dtc is indeed the cat not working correctly. you should find out why this side failed.

many things can damage a converter. like coolant being burned etc...
could be a crack in the head, coolant entering the combustion chamber . gm had a few of these defective heads.

testing/inspecting is very important when replacing these expensive items.

had a guy insist that his vehicle failed emissions because of a defective converter. he had this replaced went 10 miles back seat caught on fire. converter was cherry red.

bad injectors dumping too much fuel caused all of this !