2001 Toyota Corolla P0171B OBDII code

Tiny
MONABNICE
  • MEMBER
  • 2001 TOYOTA COROLLA
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 148,000 MILES
Hi, the P0171B code - Bank 1 system too lean has come up again on my corolla. I had a 420 code and changed cat. Converter, then had the uptake 02 sensor changed, the engine light went off and then came back on a few times after fueling with gas and finally now it is back on again. I now have had the fuel filter replaced and still the engine light is on and it is still not accelerating good when given gas. I have put in a couple of fuel injection cleaners and it gives a week of performance. However, this along with the check engine light has me worried. I was told after diagnosis it was the 02 sensor but I filled up with gas after it was put on which made the light come on. It has been reset numerous times and still says the same code 171 before I had the 02 replaced. What gives?
Please, Please help!
Sunday, August 1st, 2010 AT 11:12 AM

3 Replies

Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
Upstream sensors measure air/fuel ratio, so a lean condition indicates a high oxygen content.

If your scanner has live data mode, scan in live data and see what sensor says, should read.1 to 1V, if it stays at one voltage, it indicates a bad sensor, lean fuel ( vacuum leak, weak injector).

What brand of sensor did you use?
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Monday, August 2nd, 2010 AT 8:54 AM
Tiny
MONABNICE
  • MEMBER
  • 2 POSTS
Thanks for your reply. I used Bosch O2 sensor. The engine light has gone off now - the problem was that some technician pulled a hose loose that cause a vacuum leak. The technician that fixed it connected the hose after scanning the same code p0171. However, I now have stalling after trying to give gas by pressing the gas pedal. I believe it is either the spark plugs or its wires, a bad PCV valve, or a valve cover gasket.
Can you give me a link to show pictures or video on how to locate and check these things. I spent too much money on trying to fix the engine light all because some mechanic pulled a hose loose no one could seem to find/fix except one person in less than 10 minutes.
Thanks
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Sunday, August 15th, 2010 AT 3:31 PM
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
Try this link for info.

https://www.2carpros.com/how_to/index.htm
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Monday, August 16th, 2010 AT 8:50 AM

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