My 1999 ES 300 has been a great car thus far. The only problem I have had is the trac off and engine light come on. The Lexus dealership said it was the throttle postion sensor, and that I could get it fixed any time. The only thing I might notice is the engine cutting out.

On my last long distance trip I noticed that the overdirve was not kicking in on the highway. Also all of the lights started to pulse. They would get brighter then darker like a heart beat. The radio started to shut off on turn back on, and the acceleration was very jerky. My wife usually drives the car and when I asked her how long it has been doing this she didn't know it wasn't working properly. In any case we I got back from our trip and took it to the Lexus dealership. They siad the throttle position sensor needed to be replaced. The service consultant said that should fix the problems I am having. I drove the car back home a 50 mile trip and the lights came back on. The dealership hooked it back up and pulled the codes, then they said the knock sensors needed to be replaced. After I gave them the go ahead to replace the sensors they called back two hours later and said the transmission had a frozen cylinoid. The cost to replace the transmission would be $4,200. After I got back up off the floor I said to hold off on the replacing the trany and knock sensors. Long story short, I bought a used trany and had a local trany shop replace the trany for $1,400. When driving the car back from the trany shop the overdrive was working fine. I took the overdirve off and everything was still okay. When I had to accelerate hard to enter traffic the trac off and engine light came back on and the trany would not kick into overdirve again. Will relacing the knock sensors fix this problem, and does anyone have an idea on the plusing of the lights? The plusing usually is happening on start up and will stop after about 10 min. I would appreciate any help anyone can provide.

Thank you in advance

 

Wow sorry to hear about the problems. If it was your knock sensors that were out, you would notice the huge loss of power (limp home mode). Sounds like you have an electrical problem rather than knock sensor problems. Which lights are pulsing on and off btw other than the CEL and TRAC OFF?

 

Yes all of the dash lights are pulsing including the radio. When the headlights are on they also pulse. I have just recently discovered that sometimes when I put the car into reverse the radio will shut off. When I move it into any other gear it turns back on. Any ideas on what I can check? When you say that it doen't sound like knock sensors, can the computer give the wrong trouble code? I have not noticed a great lack of power. However, I have heard knocking upon accerlaration. I have increased the octane and this has been minimilized. Thanks again for any advice you can offer.

 

Sounds like you have more of an alternator/electrical problem more than anything else. Knock sensors can't make those symptoms you described. It has nothing to do with that aspect of the electronics other than timing retard/advancement.

 

I have brought the car to the Lexus dealership and to Autozone, they both say that the knock sensors need to be replaced. Is this something I can do myself? I understand that this will not take care of my electrical problem, but shouldn't I have them replaced?

 

That's really odd. Knock sensors can be replaced on your own. But if you're not mechanically inclined, leave it to a technician. You have 2, one for each bank.

 

I have replaced the battery and it has seemed to fix my electrical problems. Is there a book or manual I can buy somewhere that shows were all of the components are located in the engine for my 1999 Lexus ES 300? For example I would have no idea where to look for the knock sensors, but I think I could replace them on my own.

Do you know what controls the overdrive? Does the computer tell the transmission to kick in the OD? If so is it one chip? The OD is still not working properly, it is very sporatic. It may work right after startup but as soon as I stop, the OD no longer works. The OD button is not responsive. Thanks for your help.

 

Interesting, same symtoms I had and it was the battery connectors.