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What does a 4201 code mean? Volvo S60

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What does a 4201 code mean? Volvo S60

Post by JonJon55648 » Sat Jul 16, 2016 1:41 pm

Hello everyone!

I was wondering what a 4201 code mean? I have a 2001 Volvo S60 2.4l, and a check engine came up yesterday, but then went away today. I went to a mechanic for a diagnose and they brought up a code of 4201. Here is the entire code/description...


I have no idea what's going on. 2 weeks ago, I've started putting premium gas into the car. Days later, I did get a check engine light, so right away I went to Auto Zone and I got a code of P0101, which is a fuel issue. Then a day later, it went away. Now today, I got a code of 4201, which deals with the convertor. Any ideas of what might be the problem? Is it the gas? Thanks guys!
Last edited by matthew1 on Sat Jul 16, 2016 6:05 pm, edited 1 time in total.
Reason: Clarified title - please, no HELP in titles

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Re: What does a 4201 code mean? VOLVO S60 HELP

Post by chrism » Sat Jul 16, 2016 6:04 pm

According to my research, p4201 means that the catalytic converter is not working at peak efficiency. So a couple reasons that could happen is that a.) the cat really does have a problem, b.) the downstream O2 sensor is faulty and just throwing inaccurate info, or c.) the fuel/gas mixture is way off to the point the cat just can't handle it.

P0101 relates to the MAF sensor. If it's not reading intake manifold pressure properly, either due to a bad sensor, a vacuum leak, or a bad wire connection, amongst the possible reasons, it can throw off the air/fuel mixture.

I think I would look into the MAF situation first - is it connected properly? I there a vacuum leak somewhere in the intake stream? (Check all the clamps, especially if it's a turbo.) You just may find a problem there that cures everything.

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Re: What does a 4201 code mean? Volvo S60

Post by oragex » Sat Jul 16, 2016 9:00 pm

Is the flexible down pipe leaking/noisy?

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