Engine light, Code P0171

MIKETKACH

MEMBER
2001 TOYOTA CELICA
1.8L
4 CYL
2WD
MANUAL
191,000 MILES

I replaced an oxygen sensor (pre catalytic converter) and a MAF sensor. That fixed it and I cleared all monitors and passed smog. Less than one mile from smog shop it threw the same code and now continues to come back on even after resetting computer. Driving me insane. Please help.

Friday, January 4th, 2019 AT 4:09 PM

6 Replies

DANNY L

MECHANIC
5,648 POSTS

Hello, I'm Danny.

That code is for an engine running lean condition. Below I've attached a picture of things to check. Hope this helps and feel free to ask questions if needed. Thanks for using 2CarPros.
Danny-

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Friday, January 4th, 2019 AT 5:08 PM

MIKETKACH

MEMBER
19 POSTS

I replaced the MAF, pre catalytic converter o2 sensor, we smoked it and found no vacuum leaks, and the coolant temperature sensor (different code). That code is gone. It's got fuel, not running low half a tank. Only 0171 so far.
How do you check the fuel pressure? There doesn't appear to have a Schrader valve anywhere.
Thanks

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Friday, January 4th, 2019 AT 6:01 PM

DANNY L

MECHANIC
5,648 POSTS

Hello again.

Have you checked to make sure the engine (intake manifold) is not leaking/sucking air? A lean condition means excess air is entering the engine via a leak somewhere. Look for a vacuum leak as well. Yes, your fuel rail has a Schrader valve-It may be hard to find/hidden but it's there. Hope this helps and thanks for using 2CarPros.
Danny-

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Sunday, January 6th, 2019 AT 2:27 AM

MIKETKACH