On this 1990 LS400 with 170k miles, the the ""Check Engine" light was constantly on as well as the "TRAC OFF." Obviously the traction control doesnt work.

Also, soon after starting the car the "TRAC" light next to the check engine light comes on. Now when this light comes on the transmission doesn't shift right. When depress the gas pedal to accelerate, such as during an onramp to a highway, it shifts up instead of down a gear, reducing the RPM's to less than 2k and bogging the car down, not being able to accelerate.


I ran the diagnostic and these are the codes that came up:

25 - Air-fuel ratio lean malfunction
26 - Air-fuel ratio rich malfunction
28 - Main oxygen sensor signal (on right bank)
41 - Throttle position sensor signal

68 - Short circuit in kick-down switch


I would greatly appreciate any info as to what these mean and how to fix them.

Thanks

 

I am certainly not a Lexus expert mechanic, nor any kind of a mechanic, but, I wonder if your problems just might be something simple like a bad alternator?

 

Trust me start with the code 28/25 issue.I had these codes come up with codes like 21 and 28 for lean fuel etc.. and the oxygen sensor fixed it.Not no universal but original O2 sensor.They cost $90 each.The good thing with the LS is that if you fix the main code issue it wouldn't give you a run around like a freaking chrysler.

 

I figured i would buy new oxygen sensors and a tps sensor. But I didn't know how i could be getting a lean and rich error at the same time.

Also, would you advise against the universal oxygen sensors?

 

Hell yeah, I have thread on it do a search with my name and you will see all the problems I had.This was 3 months ago

 

Also, where the is the kick down switch?

 

Dont mess with anything else until you get those O2s replaced.
I am willing to bet that the rest of the codes go away once you get the front O2s replaced.
(my personal experiences tell me this)

oxygensensors.com

buy denso.

IMO dont buy aftermarket O2s, ever.

 

would that make the car run like ****???? like no power and sounds like it's missing???? lmk my car just statred to run like ****..... but my engine lite never turn on?????

 

Probably timing, ignition coils, arcing in the wires, too many possibilities.