GoldieLex

What are the first things I should do when my car is throwing code 25 and 26? I have seen some threads on this, but i wanted to address the first things i should do to trouble shoot this problem. thanks guys

meZoom!

maybe you could tell us verbatim what "the book" says about those codes? The DTC book usually have a distinct way of describing the codes and possible causes. If it's a rich/lean problem like your title says perhaps start by looking at your o2's.

GoldieLex

code 25= lean code 26=rich

VVT-i

You got a 1992 SC400, check your O2 sensors.

GoldieLex

should i just buy new ones? I am not quite sure how to check them. what other things can cause these codes? Is it probable that it is the o2's?

VVT-i

You can take it to the dealer and let them do the " O2 RPM check" by using the scan tool and they can see the wave form on the scan tool. A new O2 may cost you around $200.00 each, plus labor.

Please search for another thread that related to " O2 sensor" in the " Search ".

GoldieLex

Anyone else here ever throw a code 25 or 26 (running rich and lean)? and how was it fixed? thanks guys

silcos

This was for ls400, 1992, 178,000 miles.

I replaced o2 sensors, no luck.

Did a tune up, caps,rotors, spark plugs. Rich condition fixed -I guess new plugs helped that, but lean condition remained. Changed fuel pressure regulator (part# 23280-50010---$103.43 from irontoad.com) and all codes clear now.