dbullen

iTrader: (3)

1990 LS 400, just purchased a week ago. Today when I was driving Trac off and Check Engine light came on at the exact same time. I"ve own an 1st gen LS before for a few years but have never had this happen. Is there a way to read trac codes, or does anyone else have any other thoughs?

Also the power windows (all 4) at random won't go up, then a few minutes later it works and they will go up (Same thing from both drivers and other doors window switches). The funny thing is they will always go down. Does this sound like a drivers window switch going bad?

Kansas

Lots of issues can cause the Trac off and CEL to light up. Take your car to Autozone, dealer, etc. to see if there are any stored codes.

I remember a few past threads about window switch issues ... wouldn't hurt to search this LS400 forum using the "advanced search".

dbullen

iTrader: (3)

I read the codes, getting 21 for Engine code, and 51 for Trac code.

Looks like 21 means: 21 - Main oxygen sensor signal (on left bank)
Looks like 51 means: 51 - Problem in engine control system


Is this just an O2 Sensor? Or is there also something wrong with my trac control system? Anyway I can tell which O2 Sensor? Is there just one on the left side on the LS400?

Bradster

2 before Cat and 2 after Cat (right and left) for a total of 4 o2 sensors..Pre-Cat are usually the ones that go bad...Go to rockauto.com and pick up a pair of Denso universal sensors for a little over $100 and replace both pre-Cat o2 sensors..Follow the tutorials to splice them in...45 minute job tops..just did it on my 1990 @244K miles..