Contour Enthusiasts Group Archives Forums General Troubleshooting Single Woman Needs Help With Check Engine Light

I have a 98 Contour with 61,000 miles on it. Two days ago shortly after putting gas in, the CE light went on and has not gone off since. Unwittingly, but to my advantage, I went to have my emissions tested today and although I failed the first test I passed the second. In the process they checked my codes (yeah!) and they are as follows: P0171 (System Too Lean - Bank 1) and P0174 (System Too Lean - Bank 2). So... what do you think?? Please advise and thanks in advance. You guys are so much help!!! This is a great board!!

I really do not know but if both banks are running lean wouldn't that mean they are not getting enough gas. Maybe try having the fuel system cleaned, Ford does it for a resonable amount I think, it that doesn't help it may give some performance back. Then again maybe the O2 sensors have gone

hopefully someone else can either conferm or put down what i am thinking

This is about the same mileage I had when my O2 sensors started going. The upstreams seem to die sooner/more often than the downstream sensors. The parts are like $60 each at autozone or oreileys but probably $80-100 at the dealer. Bank 2 (front) can be changed in 15 Min. Bank 1 is harder to reach but a decent shop should be able to do it in an hour tops. Those CELs won't hurt your car but will probably drop your gas mileage a bit.

Gosh I know this is going to sound stupid and I don't mean for it too, but did you make sure that your gas cap was tight after your fill-up? If the cap is not tight (it has to click for it to be tight), this can cause the Emission Control System to signail a false system malfunction and throw up the CEL. I am not overly sure about what codes it would possibly throw up though. Maybe someone else can elaborate on this further if they think it is the cause and has happened to them in the past.

Just thought I would throw that in for good measure!

save money on o2 sensors good site if you need some. check gas cap, put fuel injector cleaner in, and reset computer (unhook battery for 15+ minutes).

Originally posted by unisys12:

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Gosh I know this is going to sound stupid and I don't mean for it too, but did you make sure that your gas cap was tight after your fill-up? If the cap is not tight (it has to click for it to be tight), this can cause the Emission Control System to signail a false system malfunction and throw up the CEL. I am not overly sure about what codes it would possibly throw up though. Maybe someone else can elaborate on this further if they think it is the cause and has happened to them in the past.

Just thought I would throw that in for good measure!

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I think you're right. I'm at work now so I can't access the service DVD but IIRC, this is one thing to check.

As for the filler cap not being tight, it is written on the cap itself. To tell you the truth, I just noticed it a few months ago while filling up myself. Just have not researched it though.

If you could check on this after work for our new friend it would help a lot.

i think I read on the board awhile ago that there is a unique code for the filler cap not being on right. I don't think that is the problem since I don't see how fuel pressure and a lean condition would go together, at least i do not think

Originally posted by unisys12:

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Gosh I know this is going to sound stupid and I don't mean for it too, but did you make sure that your gas cap was tight after your fill-up? If the cap is not tight (it has to click for it to be tight), this can cause the Emission Control System to signail a false system malfunction and throw up the CEL. I am not overly sure about what codes it would possibly throw up though.

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You are correct about a loose or faulty gas cap being the number 1 cause for a particular CEL code.
It would throw an evaporative control system leak code. (440 or 442)

However lean codes are not related. Lean codes are normally caused by intake leaks, fuel problems, and just tired O2 sensors.

Originally posted by brapple:

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I don't think that is the problem since I don't see how fuel pressure and a lean condition would go together, at least i do not think

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Lack of fuel pressure = less gas then is needed = lean engine

Normally low fuel pressure is caused by a weak fuel pump or leaking FPR.