Codes P0172 and P0175 with flashing check engine light

Tiny
ACLOLLEY
  • MEMBER
  • 2009 DODGE JOURNEY
  • 3.5L
  • V6
  • 2WD
  • AUTOMATIC
  • 167,000 MILES
Please help. My check engine light comes on and blinks. I read the code and it came back with P0172 and P0175 system too rich bank one and bank two. So of course I went to YouTube to figure out the problem. I replaced all 4 O2 sensors, spark plugs, coil packs, air filter, MAP/MAF sensor, air intake sensor, the coolant temperature sensor, thermostat, fuel injectors and the fuel rail. The light went away for about 5 miles and then came back. I took it to a shop and they did an engine compression test and that was good. They did a cylinder leak down test that was good. They did a back pressure test and bank one catalytic converter was high. The MAP sensor was reading high but I just replaced it prior to them looking at it. They pulled the plugs and 1, 3, 5 were very wet and 2, 4, 6 were damp. They suggested I replace the catalytic converter on bank one and change the plugs again. My question is, would the catalytic converters be the cause of a P0172 and a P0175? Thank you
Tuesday, May 18th, 2021 AT 6:02 PM

3 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
We need to know what the o2 sensors are reading. If the converter is plugged it is going to through the o2 sensor readings off and this could cause the PCM to think it was lean and it would add fuel to the engine.

If all spark plugs are wet or damp then clearly something is telling the PCM to over fuel the engine.

So we need to run though this testing and find out if there is a sensor issue and go from there.
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Wednesday, May 19th, 2021 AT 6:29 PM
Tiny
ACLOLLEY
  • MEMBER
  • 2 POSTS
Good Morning. Thank you for your reply. I do not have a scan tool that can do that. The scan tool I own is the ANCEL AD530. Can I still get you the data with that? Again thank you.
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Friday, May 21st, 2021 AT 4:41 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
That is okay. It appears that is only a code reader so it would not get this data. Let's do two things, first let's can you find out what the MAP sensor was reading when the mechanic said it was high?

If the pressure was high in the manifold then that can point to a restriction in the system somewhere. Which would point to an issue with the converter as well.

If this proves out, then we can test this by removing the plugs and replace them or clean them with parts cleaner and let them dry. Erase the codes.

Then unplug and remove the upstream o2 sensors and install the plugs and run the engine for a few minutes. It is going to be louder so let's just run it for a few minutes. Then remove the plugs again and see if they are still wet.

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Either way, we are going to have to replace the converter if it is restricted but at least this will help with if this is going to solve all the issues.

Let me know what happens with this and what that MAP data was when they checked it and we can go from there.
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Friday, May 21st, 2021 AT 4:42 PM

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