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Engine light came on and I attached a portable diagnostic and got a P0172 code. Does anyone know what causes this problem? And how to remedy this?
 

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Re: P0172 CEngine light, (too rich), 2005 Volvo S40 (zest4u)

Without knowing more about the car i would suspect a dirty/faulty MAF, O2 sensor, or a bad injector.<p>MAF is a quick fix, injectors may need cleaning which is a bit more complex.<br>Todd
 

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i got the check engine light come on as well and used an OBDII reader. got the P0172 system too rich as well as the P0101 mass or volume air flow circuit range/performance msgs.
would cleaning/replacing the MAF fix both msgs? i am thinking the too rich might be a byproduct of improper air reading.
any suggestions guys?

i forgot to mention, the car is all stock, it's an 05 S40 and it has 152,000 Km i picked it up used a few months ago but didn't get any service records so i am not sure how old the sensors might be and if they had been changed in the past.
 

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I have seen that fault stored before and per a volvo bulletin an ECM software upgrade is recommended. Doesnt apply to turbo models but very common due to faulty MAF adaptions values. Otherwise if turbo, I would verify the boost reference hose isnt disconnected from the manifold.
 

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i got the check engine light come on as well and used an OBDII reader. got the P0172 system too rich as well as the P0101 mass or volume air flow circuit range/performance msgs.
would cleaning/replacing the MAF fix both msgs? i am thinking the too rich might be a byproduct of improper air reading.
any suggestions guys?

i forgot to mention, the car is all stock, it's an 05 S40 and it has 152,000 Km i picked it up used a few months ago but didn't get any service records so i am not sure how old the sensors might be and if they had been changed in the past.
My money is on the fuel pressure sensor. I had one go bad and its fairly common on this car. It will either cause a too lean or too rich condition and may cause the car to hesitate.
Todd
 

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Sometimes you wont see the actual crack in the hose so push on it a bit to verify if its cracked. That will set a ECM-250a code which should be the same generic code you have set now. The old plastic upper pcv hoses crack all the time.
 

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thanks for all the input guys. i will be taking a look at things as of tomorrow. working a lot the last few days has kept me from digging into it. anyway one thing at a time and check if the msgs go away. will keep you guys posted on the progress.
 

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i checked the lines for cracks and moved them around a bit to see if i would get an other msg. no joy. i also cleaned the MAF sensor and still the same. guess cleaning the throttle body is next. if all this fails any cheap MAF sensors kicking around in the Toronto area or any on line?
 

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Check Engine

My light came on this morning. I have an 07 T5 AWD with 22,500 mi. It's all stock. It's not running hot, and a fluids check turned up nothing. It would appear from reading these comments that it should be safe to drive it to my dealer 90 miles away? Thanks for your input.
 

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Yeah you should be fine to drive it.
 

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The dealer said it is the Turbo Control Valve (TCV). They ordered the parts. I picked up the car and on my way home the light went out and hasn't come on again. I'm scheduled to have the new tcv installed on Tuesday.

I've read through some other posts where the tcv is discussed but didn't read anything that describes the tcv repairing itself and/or the ce light turning itself off once this issue has been identified.

Has anyone else had this experience?
 

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If that's the case, you should upgrade to an ipd HD TCV and toss it in yourself. There's a write up on here for that.
 

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I find it very unlikely that such a code is due to the TCV, but if they're willing to replace it under warranty, let them go for it.
 

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If under warranty, scratch what I said...free is always better!
 
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