# Catalytic Converter or DPF



## jeffreyc (Jan 23, 2015)

I have a 2014 Cruze TD. I have 231,xxx miles on it and love it. Recently my check engine light came on. I took it to the dealer and was told there was something wrong with my exhaust. The diagnostic code is P0420. Below is the report from OnStar


ECM - Engine SystemP0420The Emissions System is not performing as expected. An issue has been detected in the Exhaust Emissions System which monitors and controls exhaust gases released into the air from the engine. If the vehicle is continually driven with this light on, the emission controls might not work as well, the vehicle fuel economy might not be as good, the engine might not run as smoothly and could lead to future repairs.Service within 1 day



They recommended replacing the entire exhaust system because they 'thought' the catalytic converter was plugged. They wanted $1400 for it. 

I took it to my mechanic and he checked the back pressure on it and said it was normal. I have no loss in performance and mileage is still 40+. 

Does anyone know fan aftermarket converter I can put on? If so, where and how much can I get one for. 

Thanks in advance.


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## Blasirl (Mar 31, 2015)

A code P0420 may mean that one or more of the following has happened: 
Leaded fuel was used where unleaded was called for (unlikely) 
A damaged or failed oxygen / O2 sensor 
Downstream oxygen sensor (HO2S) wiring damaged or connected improperly 
The engine coolant temperature sensor is not working properly 
Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe Failed or underperforming catalytic converter (likely) [That could mean it needs to be replaced or just possibly cleaned.]
Retarded spark timing 
The oxygen sensors in front and behind the converter are reporting too similar of readings 
Leaking fuel injector or high fuel pressure Cylinder misfire Oil contamination


Read more at: https://www.obd-codes.com/p0420

Generally speaking you can look at the temperature of the exhaust just before and just after the converter using an infrared temperature gun. The output should be about 100 degrees Fahrenheit hotter when the engine is fully warmed up.


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## MP81 (Jul 20, 2015)

The Diesel does not have a catalytic converter, per se.

There's a catalyst in the top portion of the DPF.

I've only seen this code a couple times on the site - and seemed to be in a situation where the incorrect oil was used (i.e. non-Dexos2/Low Ash)...


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## Rivergoer (Mar 30, 2017)

If it is indeed your DPF the part number is 12659575. Pricing varies between $730-790 USD. It’s a GM part, I don’t see any aftermarket parts online.

Strange, even though it is actually a Diesel Particulate Filter (DPF), the parts listing refers to it as a Catalytic Converter.

Potayto or Potahto...whatever.

While it’s a job that CAN be DIY, it won’t be without a great deal of effort. Several of the heat shield bolts are tough to get at and there’s not a lot of room to work.


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## Blasirl (Mar 31, 2015)

Well,

Ya lern sumpin' new ever day!



Wikipedia: Diesel particulate filter

Wikipedia: Catalytic converter

What is the difference between a CAT and a DPF from a service replacement point of view?

Diesel Particulate Filters


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## Blasirl (Mar 31, 2015)

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## Blasirl (Mar 31, 2015)




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## Jondaytona (Apr 26, 2018)

I think if I ever run into this situation I would go with the DPF delete w/tune package as I've read quite a few already have done and seem to be happy with it. Plus you don't worry about DEF anymore and you can replace that with an actual spare tire.

https://www.ebay.com/itm/OZ-Tuner-E...h=item5d83f13961:g:ZM8AAOSwC~9b~Jtb:rk:2:pf:0


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## KpaxFAQ (Sep 1, 2013)

DPF is a pretty easy DIY job


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## Ma v e n (Oct 8, 2018)

The catalytic converter and particulate filter are indeed one big assembly that's connects the turbo to the exhaust pipes. GM calls it the catalytic converter and sometimes refers to it as catalytic converter DPF in the service manual.

You should be sure to replace the gasket and clamp when performing the job on your own . It's not super complicated, but it is fiddly, and the bolts and nuts involved are almost always nice and rusted. I try to replace as much of the hardware as I can usually. Note that a proper complete repair can't be done without a factory level scan tool in order to perform a DPF reset in the ECM.


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## craig85006 (Mar 19, 2017)

Rivergoer said:


> If it is indeed your DPF the part number is 12659575. Pricing varies between $730-790 USD. It’s a GM part, I don’t see any aftermarket parts online.
> 
> Strange, even though it is actually a Diesel Particulate Filter (DPF), the parts listing refers to it as a Catalytic Converter.
> 
> ...


I am having DPF issues with my 2014 Diesel. I had to have the EGR Valve replaced, and my DPF nightmare began two (2) days later.. I removed the DPF from my car and had it cleaned and tested. I replaced the DPF Exhaust Differential Back Pressure Sensor as well but, the check engine light keeps popping with the P2002 code.. I took it to the dealer and was advised that was the catalytic converter, which from what I understand, the TOP half of the unit (that connects to the turbocharger) is the catalytic converter, and the BOTTOM half of the unit (that connects to the exhaust pipe) is the DPF. 

I have a new NOX sensor coming. I am replacing the one that screws directly into the neck of the DPF. I am soooooooooooooooooooooooooooooooooooooo frustrated!

Oh, and yes, the heat shield is a major PITA to remove. I had to finagle and removed from the bottom of the car.

Craig Lambert
Phoenix, AZ


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## Snipesy (Dec 7, 2015)

craig85006 said:


> I am having DPF issues with my 2014 Diesel. I had to have the EGR Valve replaced, and my DPF nightmare began two (2) days later.. I removed the DPF from my car and had it cleaned and tested. I replaced the DPF Exhaust Differential Back Pressure Sensor as well but, the check engine light keeps popping with the P2002 code.. I took it to the dealer and was advised that was the catalytic converter, which from what I understand, the TOP half of the unit (that connects to the turbocharger) is the catalytic converter, and the BOTTOM half of the unit (that connects to the exhaust pipe) is the DPF.
> 
> I have a new NOX sensor coming. I am replacing the one that screws directly into the neck of the DPF. I am soooooooooooooooooooooooooooooooooooooo frustrated!
> 
> ...



There is generally two types of dpf clogging.
Unreacted hydrocarbons which are readily broken down in high heat, and easy to physically remove from surfaces. No problem.

And then you have the annoying kids. Big aromatic particles. Think graphene, diamond. If you are lucky these simply flake off the DPF material when they get bad... But.... Not always. They can be impossible to remove. Removal is only possible destructively.

I believe you have case number 2.

However number 2 is extremely rare. And it’s hard to say exactly why it happens since any temperature issue will give a CEL. DPFs and DOCs otherwise do not fail like on a gas engine.


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## Detrious (Jul 5, 2017)

I've looked for any info from GM regarding the ash cleaning interval on their DPFs but I haven't found anything for any of their vehicles. I know Cummins and Detroit have cleaning intervals of around 200-300k depending on the usage and size of the engine and at work under severe duty cycles on an ISB engine we do them at about 150k. Do you know if they publish this information or do they basically tell their techs that a normal service life ash clogged DPF should just be replaced and not cleaned.


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## craig85006 (Mar 19, 2017)

I am still battling my P2002 Code... I have had the DPF cleaned and did a manual regen today... still pops back on... I am getting super annoyed! HELP!


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## craig85006 (Mar 19, 2017)

Snipesy said:


> There is generally two types of dpf clogging.
> Unreacted hydrocarbons which are readily broken down in high heat, and easy to physically remove from surfaces. No problem.
> 
> And then you have the annoying kids. Big aromatic particles. Think graphene, diamond. If you are lucky these simply flake off the DPF material when they get bad... But.... Not always. They can be impossible to remove. Removal is only possible destructively.
> ...


I am still having issues with my DPF and code P2002. I had the mechanic shop do a manual regen. My car only has 110K on it... I should not be experiencing this issue!


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## Snipesy (Dec 7, 2015)

craig85006 said:


> I am still having issues with my DPF and code P2002. I had the mechanic shop do a manual regen. My car only has 110K on it... I should not be experiencing this issue!


Replace PMS sensor. Last one. Next to NOx 2.


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## MP81 (Jul 20, 2015)

Snipesy said:


> Replace PMS sensor. Last one. Next to NOx 2.


That sensor may still be covered by the special coverage warranty, no? Should be the same 120k/10 years the other parts got (though not enough - NOx2 should certainly have gotten that...).


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## craig85006 (Mar 19, 2017)

Snipesy said:


> Replace PMS sensor. Last one. Next to NOx 2.


Where is this located? Is this the sensor that screws into the exhaust pipe toward the rear axle right before the bend in the exhaust pipe? Is this the sensor that is called the DPF Back Pressure Differential Sensor? If so, I have already replaced this sensor.


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## Snipesy (Dec 7, 2015)

craig85006 said:


> Where is this located? Is this the sensor that screws into the exhaust pipe toward the rear axle right before the bend in the exhaust pipe? Is this the sensor that is called the DPF Back Pressure Differential Sensor? If so, I have already replaced this sensor.


Toward rear axle. That is the particulate matter sensor (PMS) next to the NOx 2.

What you replaced is the DPF differential pressure sensor which is located sorta behind the engine and has 2 hoses going to it.


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## MP81 (Jul 20, 2015)

Yup - last sensor in the exhaust system.









Diesel Emissions Sensor Number and Location


I'm creating this thread as a means of compiling a one-stop reference for defining, locating, and identifying Diesel Emissions Sensors for the Cruze, including part numbers and links to How To threads for repair/replacement instructions. Additional information is welcomed, as well as corrections...




www.cruzetalk.com


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## craig85006 (Mar 19, 2017)

Snipesy said:


> Toward rear axle. That is the particulate matter sensor (PMS) next to the NOx 2.
> 
> What you replaced is the DPF differential pressure sensor which is located sorta behind the engine and has 2 hoses going to it.


I replaced a sensor (Genuine GM Oxygen Sensor 12662647). This sensor is located toward the rear of the car and screws into the exhaust pipe. It's right next to the what I believe to be, NOX Position 2. The sensor has a housing that attaches to the body next to the fuel filter housing. Is this the PMS Sensor to which you refer? (See attached picture. This is what I replaced). If not, will you send me a picture of the sensor you're referring to? Looking at pictures posted by other members, it looks to be the same sensor. Thank you.


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## craig85006 (Mar 19, 2017)

A part number?


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## Snipesy (Dec 7, 2015)

craig85006 said:


> I replaced a sensor (Genuine GM Oxygen Sensor 12662647). This sensor is located toward the rear of the car and screws into the exhaust pipe. It's right next to the what I believe to be, NOX Position 2. The sensor has a housing that attaches to the body next to the fuel filter housing. Is this the PMS Sensor to which you refer? (See attached picture. This is what I replaced). If not, will you send me a picture of the sensor you're referring to? Looking at pictures posted by other members, it looks to be the same sensor. Thank you.
> View attachment 290522


Yeah that’s it. GM parts are labeled incorrectly.
Kinda annoying.


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## MP81 (Jul 20, 2015)

If you paid for it, make sure you submit a claim form: it's covered for 10 years/120k miles.



https://static.nhtsa.gov/odi/tsbs/2016/MC-10130682-9999.pdf


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