Mechanics

HELP

1999 Toyota Yaris • 120,000 miles

Help iv changed front and back lambda sensors on my 99 toyota yaris as was showing fault codes po172 and p0420 was ok but came up showing p0172
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Michellebrown
September 28, 2012.



The P0420 code is for a bad cat that code will come back they can be slow setting. What is a lambda sensor?

Saturntech9
Sep 28, 2012.
Saturntech9, Lambda = O2 sensor.

P0172 is system running too rich and this would result in the catalytic converter failing very fast as it is being flooded with fuel, causing it to overheat.

You need to check why engine is running rich. It could be faulty injectors or clogged air intakes.

KHLow2008
Sep 28, 2012.
Thanks for the slange o2 sensor conversion khlow2008 lol.

Saturntech9
Sep 28, 2012.
This lambda sensor originated from European vehicles pre-OBD-II.

KHLow2008
Sep 29, 2012.
Come to think of it in one of my gm training classes they did mention a lambda sensor lol it was a long time ago and never really heard much more about that name.

Saturntech9
Sep 29, 2012.
The term is obsolete now. Technically O2 sensors are out too. We have HO2S now which is being replaced by A/F sensors. Maybe the manufacturers are trying to confuse us so we become obsolete too.

KHLow2008
Sep 29, 2012.
Unless the car or robot can fix it they need us lol. You should have seen how bad it was with the gm ev1 while we were factory trained for it we had to go back to our hotel rooms at night and replace pages in the service manuals with new revised pages like 20-30 pages.I talked with the designers of the car that were at the gm training center and they had 6 months to make a prototype car a production car. So at that point I said I was sorry for all the bad things I said about the car lol.

Saturntech9
Sep 29, 2012.