p0171 and p2a00
 

Just stopped at O'Reilly and scanned my 2003 Honda Accord 2.4 Vtec. came back with the problem codes listed in the title.

P0171 - System too lean bank 1
p2a00 - oxygen sensor 1 bank 1

I would like to do the easy one first. Is the problem code 0171 trigerred by a bad 02 sensor. Would it make more sense to change the o2 sensor first , and if issue still around to go for the fuel pressure regulator which most of the issues point to when it comes to 0171 code.

Please help.... I love my accord but poor gas mileage and bad performance caused by these two codes are pissing me off.

Hi Member
 

PO171 code is more than likely caused by #1 A defective oxygen sensor
#2 an ignition misfire or vacume leak-repair, # 3 Fuel injector problem.

With 2 codes like you have , I would expect fuel pressure and the MAF sensor also.
Take off the MAF and have O'reilys or an Auto Zone check it for you.

WheelBrokerAng :)

would you happen to know the exact location of the bank 1 sensor 1 on 2003 honda accord 4 cylinder engine.

Change the front O2 sensor first, there's a good chance that's the reason for P0171.

Down low, between the engine & firewall. Look where the exhaust system comes down from the engine. It's #16 in this picture.
http://www.hondaautomotiveparts.com/...4sda01_b02.png

And... unless it's a California car, it probably doesn't have an MAF sensor.

I'm having the same issue. Well, actually replaced the upstream o2 sensor, then got a code for the downstream one. Replaced that, erased codes, then 24 hours later got the codes above.
P0171 - System too lean bank 1
p2a00 - oxygen sensor 1 bank 1
Advance told me that perhaps I hadn't driven it enough after the codes were reset, so I erased them again and took to the road. Everything's running fine. 24 hours later P2A00 again. What next? I saw above that the MAF Sensor came up, but it's likely only on California cars. I have a Canadian 04 Civic EX.
Thoughts?

Look on your air filter housing. The MAF sensor is #15 in this picture. Your car either has one or it doesn't...
http://www.hondaautomotiveparts.com/...4sda01_b01.png