Kimbill

The amber "CHECK" light, and engine icon, just pop on. The car is a '98 ES300 w/67k miles on odometer.

What's the best guess as to the problem?

Kimbill

steviej

iTrader: (1)

could be as simple as the gas cap is not tight or could be any one or multiple emission sensors (ie. O2, EGR, MAF) triggering a problem.

Go to Autozone. They advertise that they will read the codes for free.

You won't know until the trouble codes present in the ECU are determined.

sj

Lexmexico

What you need is someone to use an OBD2 tool, which connects to a port just underneath the steering wheel. Most mechanics have one of these, and it is not a special Lexus tool. They may check it for $5-$10 or even for free.

Steviej is probably right about his suspicions. Generally, a lose gas cap will set off the check engine light after a short time. Also a dirty engine air filter can set the engine light off.

star5

I got a 97 ls400, and 2 weeks ago, the check engine light came up, I took it to autozone today thanks for the info here and got it checked for free, and it is the problem with O2, now the question is do I have to go to the dealer for this repair, I went to the dealer (park place, plano, tx) yesterday, and they charge $120 for the check alone....:eek:

any idea such as if I could go to firestone? (they told me $89 to run the check) and it is free from autozone.

thanks a lot.

Lexmexico

I would go to Toyota. However, I had a friend with an O2 sensor problem on his 2001 RX down here in Mexico City, and a local mechanic took the part he bought at Toyota and installed it just using the service manual.

steviej

iTrader: (1)

O2 sensors are easy to install. The problem is knowing which one. If they are all the same part number, buy one, and switch out each O2 sensor until the check engine light goes away.

Be ready to do this again. If one is going, then the others aren't far behind.

The only additional investment would be the special socket (<$15) to remove the sensor. It has a special cut in it for the sensor wire to feed through.

A little antiseize on the threads and dielectric compound in the connection and you are good to go.

Its a cake walk if you only got one sensor. If you got two or three then you may have to get a second opinion.

steviej

hyperopt

O2 sensor is among the few items that I would not use an aftermarket substitute.

star5

It cost me around 350 to replace 2 OS2 sensors (one after, one before)... sensor from dealer.

a mechanic did it for me.

arfghan

Well, heck. All set to swap out the ECU, when I decided to double check...so I grabbed the new battery out of one of our classic trucks, and popped it into the gs300.
Ran the system, and Yup! the CEL flashed out the O2sensor code (21 - Main O2S & Heater Signal). Even though I had previously jumped a charge on the lexus battery, I guess it hadn't been sufficient for the 11volts needed to read codes. Duh. How dumb do I feel?
SO , NOW ... the main O2sensor.
Where is it? How easy to do myself?
And by the way, the car started right up with that battery in it, and idled perfectly. I don't trust it, so am still going to fix what the code says.