P0170 & P0171 Codes

[pyaarawala]

I just got these two codes today.

P0170 - Fuel Trim Malfunction (Bank 1)
P0171 - System too Lean (Bank 1)

The guy said that replacing the O2 sensor that is on the exhaust manifold (before the cat), should fix the problem. Was wondering if anyone has experience with these codes and how to fix them. I have another thread about ignition problems and the car shakes and shuts off, indicating a fuel problem. Do you think this is linked to that? Every time I shut off the car it does shake a little, and none of the other cars I have does that.

So changing the exhaust manifold O2 sensor will fix these codes? He resetted them for now and said if they come back you gotta do something.

 

[pyaarawala]

Okay the light came back on for these two codes, now I know I have a problem. Should I go ahead and try to replace my Bank 1 O2 sensor with an aftermarket NGK sensor?

NGK OE identical O2 sensor 24660 24660 FRONT EX, LX $267.85

That's the price for one O2 sensor from NGK? Is is supposed to be that much? Will replacing the O2 sensor even solve the problem or should I take it to my mechanic and have him look at my fuel lines and the ECU to see why my system's running too lean.

 

[pyaarawala]

no one knows? lol

 

[BlkCurrantKord]

I guarantee your fuel lines and ECU are fine. www.partsamerica.com - should have the o2 sensor a lot cheaper than that. It's where I got mine (its autozone's or advance auto's parts site).

 

[pyaarawala]

Thanks a lot BlkCurrantKord, but something weird just happened. After filling my gas tank, I noticed that the CEL light went off after starting the car. Now I didn't notice this as soon as turning on the car, but I did notice it shortly after I started the car.

I think it might come back, if it does, I'll definitely check that site out. However, is it really possible that the factory O2 sensor could just malfunction like that? Could it be due to my aftermarket header? Or the fact that I have an OEM-spec Bosch O2 sensor on my cat? Thanks.

 

[BlkCurrantKord]

Could've just been bad gas....

Yes the o2 sensor could just malfunction like that. Doubt its from the header, doubt it has anything to do with sensor in the cat.

 

[mnorton]

I have a 1998 F23A1 that has thrown the same two codes. This became very apparent this winter when the temperatures droped below -10 degrees Celcius/15 degrees Fahrenheit. As I would accelerate, the car would stop pulling at about 3700 RPM - almost like 6 air conditioners coming on all at once.

I found this Honda Service Bulletin that matched my issues.
http://www.honda-tech.com/attachment.php?attachmentid=76747&d=1255234388

I installed the new hose kit and regulator (20 minutes and very easy to do) and the problem was solved. As well, it fixed a rough idle problem that I was having when the car was fully warmed up. The two items are about $60 dollars.

I hope this helps.
Matt

I just got these two codes today.

P0170 - Fuel Trim Malfunction (Bank 1)
P0171 - System too Lean (Bank 1)

The guy said that replacing the O2 sensor that is on the exhaust manifold (before the cat), should fix the problem. Was wondering if anyone has experience with these codes and how to fix them. I have another thread about ignition problems and the car shakes and shuts off, indicating a fuel problem. Do you think this is linked to that? Every time I shut off the car it does shake a little, and none of the other cars I have does that.

So changing the exhaust manifold O2 sensor will fix these codes? He resetted them for now and said if they come back you gotta do something.

 

[AllGOnoSHOW]

Opt to close this thread due to solution being found.

 

[BMArias15]

Excellent post/find/closing by mnorton tho!

 

[AccordSeats4]

I know this thread is old but I didn't want to start a new one.

I'm still having this problem with my car. Both codes have been giving me fits. P0171 and P0170. I've replaced evap canister, gas cap, Cat... I think that was related to a p0148. Don't quote me on that though. Egr valve and cleaned out EGR port. The only thing I haven't replaced was the 02 sensor. I may attempt to try that or what mnorton has done.

If anybody has had any success with these codes. I would be happy to hear what some of the solutions are. I've been having this problem for years. Since 09. At this point I'm past desperate and a little stubborn since I don't want to go the stealership. Any help would be appreciated.