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Changed all heat senors for code P420 and replaced cat. convertor what nex

Check engine light keeps coming on

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I think you will find the aftermarket Cat Conv. is the source of your problem, but without hooking up to the factory test equipment at my disposal at my Ford dealer this at best and educated guess based on 20 years of emission related work, I am a Ford certified master electronics technician

Posted on Jan 30, 2009

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Check engine light came on after convertor was replaced. code po 137. Replaced both o2 sensors and still have the same code and check engine light

Well you would need to use a scanner to monitor the data coming from the sensor after the cat. Code 137 means the data voltage is too low or zero. The sensor generates ac voltage based on the amount of unburned oxygen in the exhaust.
The actual problem could be an exhaust leak closer to the engine, or that new cat may not be up to oem standards.

Aug 29, 2013 | 2000 Chevrolet S-10

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Check engine light code p420for toyota solara 2000

The "check engine" warning light advises that the vehicle is in "fail safe" mode. That means only some of the car's capabilities are operational, just enough to get you to the nearest service point. You probably should not drive it any further than that. Have your service man download and analize the fault codes from the ECM which will indicate what the problem is. The p420 code appears to indicate a probelem with your 02 sensors and maybe the catalytic convertor. The remedy may be to fit a new convertor but as these are expensive to replace, you may want to wait until the car has to pass an emissions test.

Apr 18, 2010 | Toyota Solara Cars & Trucks

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1999 Chevy Metro 1.0 L OBDII CODE P420. NEW O2

The o2 is just reporting information,it did not mean that it was bad,there is either restriction,in the cat,or there is a contamination in the fuel,an additive might clear it up,maybe.

Jan 19, 2010 | 1999 Chevrolet Metro

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Check Engine Light!

Yes your cat will cause it to come on...
There is a sensor before the cat that measures the emissions from your headers, then there's another sensor after your cat that measures the emissions after it passes through your cat. a faulty cat will cause the sensor to register differently triggering the light. Driving with a broken cat can cause serious damage to your engine as it also alters the backpressure

Sep 04, 2009 | 2003 Chevrolet Blazer

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I keep getting this p420 code of and on , also when my truck was only a couple of years old i had to replace the cataletic converters ,the mech told me bad gas ,is this true? and is this part of my p420...

Code p420 is a code for catalytic converter enefficiency. This can be caused by a few problems. The vehicle uses two sensors one before and one after the cat. The sensors determine how well the cat is doing its job based on how much oxygen is sensed in the air based on the rule of thumb of 21% in our atmosphere. You mentioned that these were replaced once before, and i hate to knock another technicians work without seeing it but it could be possible that the cats he installed were not OEM parts and just a generic. You can get this code from using a non vehicle specific part like that, aseasily as you can get it from a faulty pre or post cat o2 sensor.
best thing i can suggest is getting the car on the scanner and having a buddy drive it on the highway at a steady rpm, watch the 02 sensors and see if there is erattic movement or sticking, from there we can findthe next step, and FYI all catalytic converters come with a Federally Mandated Warranty period of 8 years 80,000 miles, so dont ever pay for new ones again.

Aug 27, 2009 | 2005 Dodge Ram 1500

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Engine light was on and engine idles rough.

these O2 sensors are cat convertor check sensors. id be checking cat convertors and hopefully you should try replacing if not all ready is the front bank 2, O2 sensor
if you have scanner can you see fuel trims in data display to confirm high fuel trim only on bank 2 either +-5 or more indicates problem and if bank 2 sensor 2 has fixed high 700mv reading cat no good(warm idling)

Jul 10, 2009 | 1998 Isuzu Rodeo

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Codes: PO133 02, P1133 H 025, P1134 H 025

I would try to clean out the egr valve , check for leaks at the evap canister, check the evap canister soleniod , and lastly change out the cat convertor, The cat convertor is most likely under the federal emmission warranty of 8 yrs,.80000 miles. You can take the vehicle in to have checked by local dealer or call gm customer service to check the warranty on the cat. convertor by giving them your vehicle number.

Apr 18, 2009 | 2005 Pontiac Grand Prix

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You have a V6 engine, bank one is the row of cylinders on the passenger (right) side, bank two is the row of cylinders on the drivers side (left). Your codes indicate an inefficiency in the cat on the left side but this could be due to a bad O2 sensor or an engine that is out of tune and overloading the cat. This car seems too new to have a bad cat. I would change the plugs and the O2 sensor after the cat before going any further. The reason I say the O2 after the cat, it's the one that is critical in sensing cat efficiency. What is the mileage?

Mar 26, 2009 | 2005 Mitsubishi Galant

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I think you will find the aftermarket Cat Conv. is the source of your problem, but without hooking up to the factory test equipment at my disposal at my Ford dealer this at best and educated guess based on 20 years of emission related work, I am a Ford certified master electronics technician

Jan 30, 2009 | 1997 Lincoln Town Car

1 Answer

1998 CIVIC P420 CODE

the cat is bilt into manafold and the sencer is just up abuve it

Jun 19, 2008 | 1998 Honda Civic

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