faithmkss

Hi all,

I have a 98 lexus es300. When I first got the car I thought something was wrong with the transmission as it was hesitating to shift into 1st and 2nd (sometimes) when taking off from a complete stop. I was able to override this problem by taking off in low, since that is not connected to the computer. Obviously I do not want to do this forever. So the other problem was that my speedometer would randomly go crazy while driving, sometimes upon starting the car, there is not really a pattern here. But say I am going 65 mph, all of the sudden my speedometer go to zero and then all the way to 140, all over the place then it stops and goes back to normal. While this does not effect the speed of the car, I found that this cause is related to the "transmission sensor", which would also be the cause of the shift hesitation.

Someone has taken out the sensor, cleaned it up (stating it was wet with oil, i had a horrible oil leak that has since been fixed) after cleaning it, my car would be fine for a while. But then the issue begins again. I checked codes and my mechanic said no code is coming up for this sensor and he did not see the need to replace it. Everyone I ask goes on about how the code wont come up.
All I can think is, something may be wrong with that in itself. I plan to just replace the sensor and hopefully solve the problem, but I was wondering if anyone had any advice as to why a code wont come up, could this be related to another problem? Or does this sensor not always trigger a code?
I plan to put more money into it and while I "think" I know what the problem is, I do not want to waste money when there could be another issue. Like the transmission itself. I do not think it is, since everything else shifts fine, fluid level is fine etc.
I do not think anything is wrong with the cluster. Everything else works fine.

Any advice is very much appreciated!

JetsonES

It could be a bad ground issue. My car was acting up like that, speedo and ac on the fritz until I replace the cable that goes from the negative battery post to the chassis with heavier wire. My problems vanished after that.

faithmkss

Thank you for that, I will look into it... I had a corroded battery/terminals recently. Did you happen to also have the shifting problem?
I replaced the terminals but have not checked the cable.

JetsonES

I had ac issues, the car was cutting out while accelerating, and the gauges were going intermittent, there may have been weird shifting as well but there was a whole mess of stuff going wrong at once. I used 0 gauge but I think anything 8 gauge or bigger would work. You can usually buy premade ones in 4 gauge at Wal mart or auto parts stores. Make sure to sand the area where the cable meets the chassis for good contact with the bare metal

speedkar9

+1 on the battery terminals

faithmkss

What does +1 on the terminals mean?

JetsonES

It means he likes it.