Engine Check And Trac Off Lights On

[oyu]

I have a 93 LS400 with 90K on it. One day when I was driving 60 mph on a highway for about 20 minutes, the Check Engine light and TRAC light turned on(not flashing). But the engine didn't stop and I can still drove it back home.

Then I disconnected the battery to turn off the lights because I want to see will the lights back on again. I drove around local short distance many days, the lights didn't turn on until I drove it to highway, the lights turn back on after I was on the highway certain time.

Does anyone know what is the problem? Is it related to the fuel injector or the oxgyen sensors?

Thanks in advance.

[silvermate]

do a search under "trac light", it is a very common question, and has been addressed many many times

[KY350]

I have this problem with my 91 LS. IIRC, my error codes were 51 and 55 and the knock sensor need to be replaced according to my mechanic (he use to own and race an LS400 and currently has an SC430, so he knows what he's talking about).

The knock sensor is located in the middle of the V in the engine, so there is a fair amount of work to do to get to it. Because of that, I have not replaced mine. I just turn off the engine while sitting at a set of traffic lights and restart and the CEL lights dissappear and TRAC works.

I will get the knock sensor replaced only when there is a real need to open up the engine for any other problem that may arrise in the future. Even with TRAC not operational, I don't believe that my LS has sufficient power to spin the wheels too easily in the dry - but definately want TRAC on in the wet.

[jzz30]

your trac fuse is probably blown

[KY350]

If the Trac fuse is blown, then wouldn't the Trac off light come on in the dash immediately, even after the battery was disconected? I suspect that it would not take days before coming on if the fuse was blown.

But check the fuse anyway.

[jzz30]

i dont know but this happened to me and it was the fuse. its worth a look right? and maybe the trac light doesnt turn on untill the computer tries to activate the trac?

[oyu]

i dont know but this happened to me and it was the fuse. its worth a look right? and maybe the trac light doesnt turn on untill the computer tries to activate the trac?

←

Guys:

Thanks for the suggestion. But I checked the Trac fuse over the weekend, the fuse is ok.

Any other suggestions that could causing that?

Thanks in advance.

[logic]

i dont know but this happened to me and it was the fuse. its worth a look right? and maybe the trac light doesnt turn on untill the computer tries to activate the trac?

<{POST_SNAPBACK}>

Guys:

Thanks for the suggestion. But I checked the Trac fuse over the weekend, the fuse is ok.

Any other suggestions that could causing that?

Thanks in advance.

I have the same problem, I haved a 1992 LS400 and when I start the car everything is fine until I drive around for a little while or really step on the gas than bothe the Cel and trac light come on together. I had it checked and the code came up that both knock sensors were bad.

Also where is the trac fuse located becaused I would like to check that before I shell out for knock sensors and labor cost?