mani6

Hi There,
I have issue regarding gear shifting, since I bought my lexus ES300 1999 model there was engine check and track off light was coming, I newly got license so I didn’t know about this fault, and the person who bought me this car he didn’t check anything, after 4 months i scan my car to check what is the problem, the result came with so many faults including knock sensor 1 and 2 and circuit bank 1 and 2, I replaced the knock sensors, the problem was before gear was not shifting from 3 to four gear, even I go to 120KM speed but still gear was not changing and RPM was 4400, since I know this problem and after replacing knock sensors, this problem solve some time it is changing gear but normally its like before not changing gear.

Conditions while its normal behaving:
If I have to go the 80Km direct, I mean If i, start my car and put it in full speed on the highway and press full gas pedal, then it’s going to 80KM and rpm will be 4400 than the gear will change to 4 and RPM will be reduced to 2100. In this condition my car will go smooth until i slow down car, if i slow down car for signal or turning, then fourth gear will not come. Then I have to switch off my car for 5 mints and then go again to full speed but still some times 4 gears not coming, but mostly while doing this practice it seems ok until I slow down the car less then 30KM speed.

Before replacing the knock sensers gear was not shifting at all, but now its shifting but not like normal car, so I am not sure the problem is with oil or what is the problem, I check the oil with mechanic he says its ok, still engine check and track off light is there.

Es3004ever

I bought a 2000 Lexus ES300 with the check engine light on and high RPMs I brought it to Lexus for a diagnosis knock sensors where the problem for two knock sensors harness on a thermostat I paid $1,600 I know very stupid it is my first car and I brought it to a local mechanic before Lexus for a diagnosis the next day I pick my car up they say it's most likely a transmission problem and recommend me to a transmission place like I said I did research I thought it was the speed sensors knock sensors for wheel speed sensor all these things could have caused these symptoms long story short I'll never go limp to the dealership LOL the knock sensors were $500 a piece $500 in labor plus the thermostat but the service was great they gave me a 2020 loner for 3 days for free which was pretty awesome

Steelfan

Bad knock sensor will prevent the car from shifting into Overdrive and you will get the check engine light and trac off light.
If you replace with after market knock sensors, you may get all kind of screwy things going on. You need to make sure the OEM knock sensors are used.
In my case, the shop used OEM knock sensors he bought at the dealership but, one of them was bad out of the box (sensitive, if you drop them, they are probably trashed). He had to return and redo the replacement, at no charge. Finally got it working.