Catalytic Converter & MAF sensor

You mentioned some DIY type maintenance so you might consider this. A vacuum gauge can be purchased cheap and not only are they very easy to use they can quite likely tell you if there’s a compression problem without doing a compression test.

Harbor Freight has one for about 15 bucks or so. Just unplug the vacuum line at the fuel pressure regulator, connect the vacuum gauge to the vacuum line, and start the engine. The gauge reading will let you know if there’s a problem worth digging into as far as compression goes.

Readings vary based on a number of factors but if the needle is rock steady at 19-20" of vacuum then you’re likely ok on compression. If the needle is at 14-15ish or vibrating/wobbling then there’s an issue that needs to be dug further into.

I don’t know if this is an area you feel comfortable going into and I make the suggestion only because of the prior comment and the fact that it’s an easy and cheap diagnostic step.

Asemaster, I trust and agree with your opinion because that’s what I felt as I am diagnosing my car.
My car is a chevy cruze 2011, with a P700 catalytic deficiency code, and occasionally p1101 mass air flow sensor. I have checked everything with the sensor and the duct, its all clean. There is a bad smell coming from the car, do you think my first priority should be replacing the Cat.?

Matthew_Mo, your better course of action would be to start a new thread, with a new title, and explain your situation, and describe drivability problems as well as codes read. Thanks and good luck.

Hi there!

I have a Volvo S60 (turbo) from 2005. She almost all the time had an engine light on (I bought it this way), but was told it might be just a sensor. Mechanics would reset it when I had to get it inspected.

  1. Took the car to the mechanic to get it checked for maintenance. He changed the air filter and added some oil. He also found some codes such as 140C, 140D, 120D, and 400C. Told me there might be something about the catalytic converters but that is too soon to tell.
  2. A few days later the maintenance message came to my dashboard. The mechanic changed the oil, oil filter.
  3. Next day I drove the car many miles. Then the day after the dashboard said “reduced engine performance” and stopped running (in idle).
  4. He told me the throttle body needs to be replaced. We replaced it and was told to bring it back if the engine light comes back. It did!
  5. Took it to AutoZone to read the engine light and they said it is a code for the catalytic converter. I just needed to double-check.
  6. Went back to my mechanic and he told me to buy this special additive to add to the fuel tank to “clean” the converters. He took out the engine light to see if it comes back after I drive it with this additive inside the fuel tank.
  7. Engine light came back on and the codes were air mass flow and catalytic converter. This back and forth happened twice (same codes appeared).
  8. Today he told me to change the air mass flow.

I am a female so my car mechanics knowledge is limited, hence, that’s why I am here.
Is there a connection between air mass flow and a catalytic converter? What about the throttle body in connection to the catalytic converter? What other options do I have to make sure it is not the catalytic converter? What other tests can he do on her to rule out the converter?

Thanks for your help and advice.

Tagging onto a three year old thread about a '98 Nissan Maxima is not the best way to get helpful suggestions regarding your 2005 Volvo. You should start a new thread for your car and its problems.

If you click on the gray button ("+ New Topic") in the upper right portion of your screen, you can begin your own thread.

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