JMReid91

So I have a new issue with the old car. I drove about 200 miles and the car was fine, but when I started to go back the other direction from my trip after a few days of being there, my cars transmission started to act very odd. It would stumble through the gears, jump up and down or not go back into low gears once I was at a high speed. Also the reverse quit working temporarily. So my first thought was the ECU has gone bad, so I replaced it with a used one today, but the problem persists, so now I'm looking into the Vehicle Speed Sensors next to see if this fixes my issue. My speedometer is reading correctly and I have no codes throwing either. I've even tried shifting it manually with O/D and it still jumps back and forth through the gears.

During my research, some information is showing that there is 2 speed sensors one near the bell housing of the transmission near the fire wall (which I found) and a second one that is supposedly near the starter on newer models or somewhere else that I can not find. Does anybody have any suggestions if the 1993 has 1 or 2 speed sensors on it because it is driving me nuts trying to find it. The images I uploaded below has one image showing 1 VSS which I can find and the other showing 2. Or possibly have another suggestion to the issue I'm having with the car stumbling through the gears.

ShSh

As far as I know the sensors are on the transmission usually less than two feet apart. I just opened and cleaned mine but I have to change them with new ones. I lifted the car (driver side) and went under the car and say them both on the transmission body. Not too hard to get to. Little tight area but managable. I have a 2003 Lexus GS300. I'll see if I can find a picture to upload for you.

ShSh

ShSh

Arsenii

Hello,

Here you can find more detailed pictures of your transmission.

The diagram you linked above appears to be correct, the sensors are places quite far apart and on different sides of the transmission apparently. No 1 sensor in your diagram is on the front with 3 wires coming out of it, a little to the Right of the Selector Switch. No 2 sensor is located on the Back of the transmission, under the metal plate, it would be quite tricky to access. I would try unplugging them one-by-one first to see what happens before replacing them.



Hope this helps and best of luck!

ShSh

Hey thanks for the photo. Is this a GS300 1st gen? I have a 2003. I actually went under the car and opened and cleaned the sensors. They were both on the driver side of the tranny about 2 ft apart. I also tested them and they both had a 680 ohm resistance. I don't know what they should be but I've seen cips and articles talking about 2400 ohms. Anyway the fact that both had the same numbers and yet only one of them is sending an error code (P0717) is disconcerting
I ran some Qs on chat GPT and it told me if one is bad is good practice to change both so I'm ordering both as OEM parts from Japan. I'll post here how it goes and I ill make a video clip of the location next time I get to them. Cheers

Arsenii

Well this is an ES forum, not GS, here is a link to a forum section for your car.

Resistance test is not always the gold standard for those, a better way would be to measure AC Voltage across the Pins while waiving the sensor over anything made of Steel, you won't see anything if the sensor is toast.

I am yet to see two sensors fail at the same exact time, something remarkable must come by to make that happen.

Emmmm, riiiiiight.. Yeah, that's first for me asking higher powers to diagnose your car...

Aanyway, those sensors tend to last a while, the fact that even one of them got cooked is strange all on its own, so I would suggest to only replace one for now, as it is not like they are hard to access. At least we don't have to worry about AI invading just yet.

Hope this helps and best of luck!