Service engine light on and codes PO101, PO410 and PO442

JAREDR123

MEMBER
2003 CADILLAC DEVILLE
4.6L
V8
AUTOMATIC
118,000 MILES

My service engine light is on and there are three codes. One is po101 which is the mass air flow sensor I believe. Another code is po410 which is secondary air injection and another code is po442 which I am not too worried about. I recently took it over to koehne GMC and they told me I need a new catalytic converter. He told me the mass air flow sensor is going off because my catalytic converter is plugged. Is this true? Or can that happen? He said if I replace my catalytic converter, the mass air flow sensor (po101) light will go off. My car jerks everyone once in a while only when I go above like 65 mph. Also I feel like my acceleration should be faster, especially when I'm going 40 and then pin it. It doesn't really kick in a whole lot or it's not really smooth. It's good when I stall, I don't really lose power. Do you think a bad mass air flow sensor is doing this? Should I just get a new mass air flow sensor first or get a new catalytic converter? And what about the po410 code. Is this something with the air pump, air filter or what? Let me know what I should do?

Tuesday, December 30th, 2014 AT 7:36 PM

3 Replies

CADIEMAN

MECHANIC
3,544 POSTS

Check the converter by removing the o2 sensor in the exhaust. Does the power come back?

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Tuesday, December 30th, 2014 AT 8:01 PM

JAREDR123

MEMBER
29 POSTS

The power never goes out. It never loses power. When I stall it's fine. I feel like it should have more power when I accelerate my car.

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Tuesday, December 30th, 2014 AT 8:18 PM

JACOBANDNICKOLAS

MECHANIC
110,114 POSTS

Hi,

The idea that you really don't feel a loss of power usually is a good indicator the converter isn't plugged. The P0101 code you have is directly related to the mass air flow sensor (MAF).

Before replacing parts, lets first confirm the MAF or an electrical issue is the cause of the problem. I attached pics below. They are a step by step flow chart for testing related to the P0101. I recommend reviewing and completing those first.

See pictures 1-5

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Now, the P0410 deals with the secondary injection, as you mentioned. That could be related to a few things, including a simple relay fuse for the air pump, a leak, a bad O2 sensor, or the pump. The diagnostic flow chart related to this code.

I am attaching the diagnostic flow chart related to this code.

See pics 6 - 21.

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You also indicate code P0442. That code is relate to the EVAP system. The code is indicating there is a small leak in the system. From experience, the chances of finding a small leak is very slim by simply looking for it. In this case, I recommend having the EVAP system smoke tested. This procedure injects smoke into the EVAP system. Some will exit where the leak is located.

Please let me know if this helps or if you have other questions. As far as the initial issue, I don't feel the converter is plugged. I suspect the issue with the MAF is causing the issue with the exhaust (secondary air injection) issues.

Let me know what you find or if you have other questions.

Take care,
Joe

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