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Trac And Engine Warning Lights On


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For a while just the Trac light was blinking over the speedo (well, turning off and on intermittently). But then it stopped coming back on. A few hours later the Check Engine light came on along with the Trac Off light on the lower left of the console.

As far as I can tell, there are no performance problems with the engine. It revs normally and has normal power (it seems, its not like I put it on a dyno...).

I'm assuming the TCS is breaking or broken then. But I wanted to know how likely it is that the engine is going as well? I can deal with broken TCS, but a broken engine...

Thoughts?

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It sounds like you have a error code. Could be a lot of things. Best thing would be to check out what error is being generated. Search on the forum for ODB I error code. That will give you the way to check the error and then tell us what error # is it.

We can advise from there.

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Okay, I used this link here: http://www.lexls.com/tutorials/intro/codereading.html.

I was able to get ahold of a code for an Engine fault but was surprised to find that the Trac system was reporting no faults at all. The engine fault code that came on was 25 - Lean fuel mix. I found another post on this forum that talked about it a bit and decided to get some SeaFoam to see if maybe the engine needed a bit of cleaning. Then I went out and drove it around to heat the engine up a bit... :).

Now, after the drive, the Trac light in the Tac will come on a bit of a ways into a long drive and stay on. (Is that a good thing? Is it supposed to be on or off?) The car does seem to have pepped up a bit since I put in the SeaFoam. Though, to be fair, that could be a placebo effect...

Oh, I also checked my air filter and found that it is old and has holes in it (I just bought the car, not my fault...). I'll be replacing it tomorrow first thing. (Which reminds me, the car looks like it wasn't terribly well cared for, any other maintenance I should be running on the car at 109,000 miles that may have been skipped? I know the oil is clean and everything that is easy to see looks good, what about internals though?)

The Check Engine light and the Trac Off light remain on. I tried to follow the instructions on the other post to turn them off but couldn't find the fuse, I think my car model might be different. Where is that fuse to clear the warnings on a 1992 SC400?

Oh, while I was getting the Engine Fault Code the O/D light was blinking like mad continuously. Is that supposed to happen or should I be worried?

Sorry for the confusing post, there are a few things happening at the same time... Thanks for the help so far!

PS - Any idea where I can find a repair manual for this thing? I can't seem to find one anywhere...

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Don't worry about the TRAC light. It comes on whenever the engine shows an error. To clear the error code you can unplug the battery terminal, wait a minute and replug, but don't do that yet. Your error light will come back on.

Good thing you caught the Air Filter. I generally prefer the K&N or another washable filter since they do get dirty and it would be waste of money to keep having to buy a new one. I haven't used Seafoam before because I heard others say the fuel injectors can get clogged. I have heard others use ZMAX to cleanse and lubricate but don't really think it's needed if you maintain your car specially changing the oil and filter. Sicne your car is historic, I would also check out the spark plugs

THe code 25 error could still be a number of things. Start with the EGR tubes and injectors. Clean them out with some carborator/injector cleaner. Once done. reset your computer and drive. 10-20 minutes should trigger the error code to come back with the same or different code.

Hopefully, the error isn't being caused by a failed o2 sensor.

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Mkay, I'll take a look at all of that stuff first and see what happens. Do you know of any instructions on how to clean those things out?

Also, I'm still confused on this, the TRAC light in the middle of the odometer. Is that supposed to be on or off? I know the ones in the lower left ought to be off, but I'm unclear on the one in the middle of the odometer...

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Al the lights are supposed to be off unless you have an issue. Let's solve one thing at a time.

I don't remember where the EGR valves are on the UZF1 engine but based on the pictures it's off the IAC Valve.

Someone posted this on an old post. see attachment.

Testing and Inspection EGR Valve.pdf

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Sorry, haven't had a chance to download that pdf until today. I'm looking it over...I'm a bit of a newb (okay, a lot of a newb), but I'm trying to learn so bear with me.

Firstly, what amount of resistance is considered normal operation? It says: Resistance(Cold): 19.9 - 23.4 ohms. Is that normal operation or is that the range I should be worried about?

Secondly, do I really need to drain the coolant and (probably a really stupid question) can I reuse the coolant after it's been drained or is that a bad idea?

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It should mean, while your engine is cold use 19.... ohms.

You could re-use the drained coolant but I would ask what for? Amazon sells the Toyota red-coolant online. I would buy that.

While you've got the coolant drained, I would consider replacing the thermostat sensor if you know for a fact the water pump has not been replaced within the past few years.

I don't think you've mentioned how many miles and what kind of service history the car has. This would be a good time to think about protecting your investment.

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Same thing just happened on my '09 RX350. Took it into the dealer and they charged $110 to reset the computer. Their explanation was that apparantly the gas cap had not been turned tight enough and that this triggers the "check engine" lite because of lack of pressure in the gas tank. This then reduces the power to the Trac system which reduces its ability to perform properly (or something along that line of explanation).

I'm not sure that just resetting the computer is the answer or how this is done, but $110 wasn't to big a price to pay for the peace of mind that it was handled properly. I was 2,000 miles from home and had to drive through the mountains to get home. The Trac system would have been useful if I hit some bad weather.

Good luck...

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Jay: I had a similar problem on my RX300, and checked the club forum. Someone asked if I had had my oil checked recently. Turns out there is a hose that attaches to the rear of the air filter assembly, and when they take your air filter out to show to you, the hose sometimes gets detached. The solution, as I recall, was to put that hose back on the nozzle on the rear of the air filter assembly, disconnect the negative battery terminal for 5 minutes, hook it back up and all is good. Don't know why that would make the trac light come on, but it did, and the fix worked for me. I was prepared to spend thousands on a transmission repair! Hope this helps.

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