Driving with check engine light?

[snoopdoug1]

My check engine light came on last night, and I took it into Autozone to get the codes read this morning. The codes it printed out were:

P0170 - Fuel trim malfunction(bank 1)
P0171 - System too lean(bank 1)

The book at autozone said:

"The powertrain control module uses the oxygen sensor to calculate the air/fuel ratio of the engine. The computer has recognized a rich or lean condition on one engine bank only. Possible problems:

1) If bank one and two codes sit together suspect fuel pressure or MAF(max air flow) sensor.
2) Oxygen sensor defective
3) Ignition misfire or vacuum leak repair
4) Fuel injector problem
5) Low fuel(of course, I can rule this one out on my own)

My question is... is it safe to drive with this? I won't even be able to call the shop until tomorrow... Also, anyone have any advice on what they think the solution would be, as well as a guess as to what it would cost?

Thanks

UPDATE:
Driving to the shop, the check engine light went off so I cancelled my appt... Should I still have taken it in? Seems to me if the "idiot light"(re: check engine light) goes off then the car thinks it's back to normal...

 

[funboy6942]

Can damage the cat if driven for too long, few days, little drves, I dont think is going to hurt too much, IMO. That really about all your going to harm, and since its a lean code your actually going to get a minimal gas savings

 

[maddogchen]

what kinda car?

I had that problem with a Nissan Maxima. After a few times the car refused to start till i reset the codes. I eventually just replaced the oxygen sensors, all 3 and it worked.

 

[snoopdoug1]

Originally posted by: maddogchen
what kinda car?

I had that problem with a Nissan Maxima. After a few times the car refused to start till i reset the codes. I eventually just replaced the oxygen sensors, all 3 and it worked.

Sorry - forgot to mention that. It's a 1999 honda accord.

 

[snoopdoug1]

Originally posted by: funboy42
Can damage the cat if driven for too long, few days, little drves, I dont think is going to hurt too much, IMO. That really about all your going to harm, and since its a lean code your actually going to get a minimal gas savings

lol - thanks for pointing out the positives Yeah, I was planning to call the shop tomorrow - will have probably put 30 miles on it by then between driving to a volleyball game tonight and also going to work tomorrow. I was planning to call the shop first thing tomorrow and get it in ASAP. I am still debating going to the volleyball game tonight...

 

[TheSlamma]

It's not safe to drive lean, it's "okay" to drive short time if it's rich but lean can really trash some stuff especially if you start getting detonation.

 

[snoopdoug1]

Originally posted by: TheSlamma
It's not safe to drive lean, it's "okay" to drive short time if it's rich but lean can really trash some stuff especially if you start getting detonation.

Hmm - lean means it's not getting enough oxygen in there right? So the detonation would be more powerful w/o the oxygen? As you can tell, I don't know much about all this stuff...

 

[funboy6942]

Originally posted by: TheSlamma
It's not safe to drive lean, it's "okay" to drive short time if it's rich but lean can really trash some stuff especially if you start getting detonation.

Anti knock sensors wont let it get that bad
And if it shout sound like the engine is making a ticking sound when you give it gas to pass a car or going up a hill may be best them to take it to a shop asap and just rent a car. But I doubt its is running that lean, it would really have to be lean to start that and there are so many other sensors and crap to prevent that from happening, since it is just showing a lean code and nothing more. Hell if anything the computer is already making up for the failed systems that popped the lean code and made sure its not "running" lean right now, if that make sense. If not I will try to word it another way for you.

 

[BUTCH1]

What's the mileage on the car?? I'm assuming it's a V6 (2 O2 sensors) I replaced an O2
sensor on my last car@110K, stopped a lean run condition, Good luck.

 

[funboy6942]

Originally posted by: snoopdoug1

Originally posted by: TheSlamma
It's not safe to drive lean, it's "okay" to drive short time if it's rich but lean can really trash some stuff especially if you start getting detonation.

Hmm - lean means it's not getting enough oxygen in there right? So the detonation would be more powerful w/o the oxygen? As you can tell, I don't know much about all this stuff...

That would be rich, to little O2 and to much fuel mixed with it. Really dont think to much into it, your car has sensors to make up for failing sensors till it hits a spot it cant make up for at which point your car would run like sh1t or not at all. Your not complaining about power loss, pinging noise from under the hood, or anything really out of the ordinary so its just something that failed, the computer popped the light on for it, it making up for the problem till you can get it fixed. Drive it till you can get it into the shop.

Again if it starts to make a ping or a pop sound when going up hill, under heavy take off, or passing, can use a high grade octane fuel, or just rent a car till it goes into the shop.

 

[snoopdoug1]

Originally posted by: BUTCH1
What's the mileage on the car?? I'm assuming it's a V6 (2 O2 sensors) I replaced an O2
sensor on my last car@110K, stopped a lean run condition, Good luck.

It's got approx 92,000 miles. It's a 4 cylinder.

Thanks

 

[BUTCH1]

Originally posted by: funboy42

Originally posted by: TheSlamma
It's not safe to drive lean, it's "okay" to drive short time if it's rich but lean can really trash some stuff especially if you start getting detonation.

Anti knock sensors wont let it get that bad
And if it shout sound like the engine is making a ticking sound when you give it gas to pass a car or going up a hill may be best them to take it to a shop asap and just rent a car. But I doubt its is running that lean, it would really have to be lean to start that and there are so many other sensors and crap to prevent that from happening, since it is just showing a lean code and nothing more. Hell if anything the computer is already making up for the failed systems that popped the lean code and made sure its not "running" lean right now, if that make sense. If not I will try to word it another way for you.

You are correct Funboy, if the PCM sees things getting too far out of wack it will run the
car in "limp" mode and give it extra fuel to avoid detonation and knock. In this mode
readings from the O2 sensor are ignored, just like when the car is first started it takes
1-2 min. for the O2 sensor to heat up. My car is actually a little bit peppier when it's
cold..

 

[snoopdoug1]

Originally posted by: funboy42

Originally posted by: snoopdoug1

Originally posted by: TheSlamma
It's not safe to drive lean, it's "okay" to drive short time if it's rich but lean can really trash some stuff especially if you start getting detonation.

Hmm - lean means it's not getting enough oxygen in there right? So the detonation would be more powerful w/o the oxygen? As you can tell, I don't know much about all this stuff...

That would be rich, to little O2 and to much fuel mixed with it. Really dont think to much into it, your car has sensors to make up for failing sensors till it hits a spot it cant make up for at which point your car would run like sh1t or not at all. Your not complaining about power loss, pinging noise from under the hood, or anything really out of the ordinary so its just something that failed, the computer popped the light on for it, it making up for the problem till you can get it fixed. Drive it till you can get it into the shop.

Again if it starts to make a ping or a pop sound when going up hill, under heavy take off, or passing, can use a high grade octane fuel, or just rent a car till it goes into the shop.

I haven't noticed any power loss(it's a 4 cyl anyways, so it doesn't have any power to lose!) I haven't heard any ping's or pop's, so I guess it's ok for now. It does seem to make a little noise when I go into neutral or park, but that could have always been there for all I know and it also goes away after a few seconds.

Thanks again for the help.

 

[d3n]

I think issues like this are sometimes brought on by the vapor recovery system in the fuel tank . People topping off at the pump can actually flood the emissions system with fuel if it reaches the valve. Eventually you end up needing a new cat or new sensors. May not be related to the ops issue but I thought I'd throw that out.

 

[snoopdoug1]

I also forgot to mention I'm pretty sure the cat is fine. I replaced it about 3k miles ago.

 

[drnickriviera]

MAF sensor, had the same trouble codes in my fathers Lexus. Even though the test in the factory manual said it was ok. It's safe to drive as long as you aren't flooring it up a mountain with the engine pinging.

You may try cleaning the MAF first. It will be between the air cleaner and throttle body. Take a picture of that area if you can't find it.