Help - OBDII error code "system running lean" - Toyota Yaris Forums

Gazdaman · 05-14-2009, 12:06 PM

Hi,

my girlfriend's had a 99 Yaris for a few years now. The engine light's been on for a while, and it's been a pain picking up off idle, worse when cold.

It runs fine, other than this flat spot very low in the rev range. And returns good mpg.

Anyway, I bought an OBDII error reader which read code p0171 which is "system running lean".

So I'm guessing it's a sensor, but I don't know where. I replaced the spark plugs recently which didn't help. A clogged air filter would make it run rich. So I'm thinking dirty injectors? Dodgy fuel management? Lambda sensor?

Anyone got any input?

Ga

Tamago · 05-14-2009, 12:09 PM

could be a bad oxygen sensor
could be clogged injectors.

i'd start with the o2 sensor first.

Gazdaman · 05-14-2009, 12:10 PM

Just checked eBay WOW they're expensive! Might try a breakers.

Gaz

Tamago · 05-14-2009, 12:30 PM

Quote:

Originally Posted by Gazdaman

Just checked eBay WOW they're expensive! Might try a breakers.

Gaz

in the US they're around $100..

http://www.google.co.uk/products?q=o...sor+1999+yaris

yaris-me · 05-14-2009, 12:34 PM

Try using a good fuel injector cleaner in your gas. If it shows improvement, run it again.

05-14-2009, 12:06 PM	#1
Gazdaman Drives: Corsa 1.2 8v Join Date: Jan 2009 Location: Leicester Posts: 5	Help - OBDII error code "system running lean" Hi, my girlfriend's had a 99 Yaris for a few years now. The engine light's been on for a while, and it's been a pain picking up off idle, worse when cold. It runs fine, other than this flat spot very low in the rev range. And returns good mpg. Anyway, I bought an OBDII error reader which read code p0171 which is "system running lean". So I'm guessing it's a sensor, but I don't know where. I replaced the spark plugs recently which didn't help. A clogged air filter would make it run rich. So I'm thinking dirty injectors? Dodgy fuel management? Lambda sensor? Anyone got any input? Ga

05-14-2009, 12:09 PM	#2
Tamago View User's Garage Drives: ZZW30 Join Date: Dec 2006 Location: Off Grid Posts: 4,904	could be a bad oxygen sensor could be clogged injectors. i'd start with the o2 sensor first. __________________ Been a long time messing with cars..

05-14-2009, 12:10 PM	#3
Gazdaman Drives: Corsa 1.2 8v Join Date: Jan 2009 Location: Leicester Posts: 5	Just checked eBay WOW they're expensive! Might try a breakers. Gaz

05-14-2009, 12:34 PM	#5
yaris-me Learn to Relax Drives: 2007, Meteorite, LB Join Date: Dec 2008 Location: Anaheim, CA Posts: 2,070	Try using a good fuel injector cleaner in your gas. If it shows improvement, run it again.