95 Lexus Es300 4 Bad Sensors Trying To Figure 1 Out

[igbeserk]

I took my car to cottman transmission today to get the tranny checked out. since last weekend its been having shifting issues. mainly around the first gear. It could have just been the motor mount because I had that replaced before and then again 6 months later. I also had replaced the transmission a few months back also. But anyway I go there I get it checked out. They tell me that I have 4 bad sensors. 2 in the transmission and 2 in the engine. They had a paper printed out yet they would not give it to me. I can only remember 3 out of the 4 he told me. The 2 in the engine are one of the O2 sensors and the Knock sensor. The tranny one is the speed or speed control sensor forgot what he said exactly. The last one escapes me I can't remember the name. He also told me to look at it this way one of them is the input and the other is the output. I looked in the haynes toyota guide i have and for transmission there's 3 sensors. two speed ones and a throttle position sensor which if goes bad can cause the symptoms i've been having. But I don't remember that being the name. I am wondering if there's any other sensors that i might have not seen for the tranny.

Any help would be appreciated. I also am trying to make sure if this car has an OBDI or OBDII sensor. I took a picture. thanks

http://img638.imageshack.us/img638/8431/img1221e.jpg

[George_Jetson]

That is a OBDII connector, so I would recommend taking it down to the local auto parts store and asking them to read the codes, and write them down so that we can give you more concise information.

There are two "speed sensors" for the trans, The throttle position sensor is for the engine.

[igbeserk]

my friend had an OBDII scanner so I used that to get the error codes. I got 4 error codes.

P0135

P0325

P0500

P0720

Those are the error codes.

[George_Jetson]

P0500 and P0720 are for the two speed sensors on the trany. One is measuring the input speed ( basically the engine rpm minus the slippage in the torque converter) and the other is the output speed sensor. The ecm compares both sensors to determine if the trans in operating properly. The output sensor is also the same one used for the speedometer, so I am surprised that you did not mention a issue with this. So I would start with checking the wiring and both of these sensors.

P0135 is for O2 sensor, bank 1 sensor 1 ( the one next to the firewall ). The heater is probably open. You should measure the resistance of the heater, and replace if it is open. I would not look at the knock sensor until after you have the other three codes cleared. And I would not be looking for a trans problem until you have the 500 and 720 codes repaired. The ECM detects a input error, so you cannot expect it to output the correct commands until it receives the correct inputs. IE the shift points till be jacked up big time.

[igbeserk]

all right so check them using a multimeter or something? and the tranny sensors would be accessable underneath the car correct?

[George_Jetson]

There is a link at the top of this forum, marked Marry Christmass Factory service manuals. Get the one that is closest to your car, it will show you where the sensors are, and how to test them. You need to get the three sensors functioning, it is possible that the 4th sensor is not bad, but either way, that is the last one I would look at.

[igbeserk]

I finally got around to messing around with the sensors. all this rain we've been having has made it a problem. Anyway, me and my friend we really didn't do much we took out the O2 sensor the one located in front of the engine and we took the one in the under the car near the cat just to look at it. they looked somewhat old and corroded but we cleaned them off with some electric component cleaner. We also replaced my air intake he gave me his from his car instead of the filter and all that comes with the lexus by default. I doubt it had anything to do with it but i mention it anyway. So we cleaned those two then we cleared the error codes using the ob2. Ran the tests again and now only 1 error code instead of 4. The only error code now is the knock sensor, which we couldn't get to because we don't have the time but will probably look at next week. I drove around for a bit. hitting the 40-80's and i tested it when i got home still only one error code being read now. I guess what you said was right George trying the first ones first and the others will probably go away. I'll try it again next week to make sure.

I still have the ABS light though so I guess it wasn't the sensors in the tranny. Anything else I could try or look into?

thanks for all the help thus far.

Also later that day another error code came up. The O2 sensor one again so i'm going to just replace that. And checking the car this morning still just two codes.

[mrlexluter2]

well my input being i got a simular problem still working on <_< I do know the Oxygen sensor has nothing to do with the shifting and for you to take it there and they didnt want to give you a print out sounds like they wanna get ya so i report that if you want i hate those type people but anyway.....I thought it was the car speed sensor and the tranny speed sensor? real talk.. you get around to it just replace them all one at a time so that wya you have that not to worry about in the future and those sensors are nothing to replace you just get down there the tranny by the fire wall 2 bolts pull it off the car one on the case one bolt pull it off hope that can help

[igbeserk]

cool i'm grateful for the input gives me a better idea of where they are. Yea I really don't think those sensors are bad to begin with. Because I replaced the tranny back in october or so. The mechanic who did it didn't believe i had an OBDII port in my car and after you do work on a car that's given you some error codes you have to erase it i believe the code just doesn't go away on its on. so i think those two codes are just from the old tranny that was in there.

I will try to look into them after i replace my motor mounts. The second one i had put in after the first one only lasted me briefly has a crack in it and I think thats causing some of my shifting issues. So i bought an actual toyota OEM mount this time around and I also bought a rear mount since I never replaced that. Hopefully once i put those in my shifting issues are done for. I'll replace the O2 and the see about the Knock and hopefully after that its smooth sailing. I still need to figure out my ABS light issue and Airbag light issue. Both of those can be caused by having the battery disconnected for too long but looking into it I'd have to go to a lexus dealer to get those removed. So i'm not sure.

[mrlexluter2]

cool i'm grateful for the input gives me a better idea of where they are. Yea I really don't think those sensors are bad to begin with. Because I replaced the tranny back in october or so. The mechanic who did it didn't believe i had an OBDII port in my car and after you do work on a car that's given you some error codes you have to erase it i believe the code just doesn't go away on its on. so i think those two codes are just from the old tranny that was in there.

I will try to look into them after i replace my motor mounts. The second one i had put in after the first one only lasted me briefly has a crack in it and I think thats causing some of my shifting issues. So i bought an actual toyota OEM mount this time around and I also bought a rear mount since I never replaced that. Hopefully once i put those in my shifting issues are done for. I'll replace the O2 and the see about the Knock and hopefully after that its smooth sailing. I still need to figure out my ABS light issue and Airbag light issue. Both of those can be caused by having the battery disconnected for too long but looking into it I'd have to go to a lexus dealer to get those removed. So i'm not sure.

Well I kinda had the same issue with shifting and the motor moounts really dont have anything to do with it i dont think but it's good to replace 'em and far as the codes go if you keep driving and nothing really wrong the computer should reset itself automactlly with out you unpluging the battery try going to autozone see if those codes come up there if you're car has'nt already reset by now ;) and the abs goes i know i need to clean my abs sensor maybe youdo to my brakes works just fine so if your works good then you know it's not your braking system might just need to clean you abs sensor as i type this bout to do the same to see if my light goes off i pray it do

[mrlexluter2]

P0500 and P0720 are for the two speed sensors on the trany. One is measuring the input speed ( basically the engine rpm minus the slippage in the torque converter) and the other is the output speed sensor. The ecm compares both sensors to determine if the trans in operating properly. The output sensor is also the same one used for the speedometer, so I am surprised that you did not mention a issue with this. So I would start with checking the wiring and both of these sensors.

P0135 is for O2 sensor, bank 1 sensor 1 ( the one next to the firewall ). The heater is probably open. You should measure the resistance of the heater, and replace if it is open. I would not look at the knock sensor until after you have the other three codes cleared. And I would not be looking for a trans problem until you have the 500 and 720 codes repaired. The ECM detects a input error, so you cannot expect it to output the correct commands until it receives the correct inputs. IE the shift points till be jacked up big time.

[igbeserk]

Went to the mechanic today to get the mounts looked at. The rear mount was loose and really needed some serious tightening. and the front mount was cracked. Had it replaced. shifting much better now.

Going to look at the knock sensor tomorrow and most likely replace the O2 sensor tomorrow also.

Change the cluster needles but now the speedometer needle won't move :-/ i don't think i broke it cuz it was easy to remove and add the new one no force was applied really. might be that one of the cables are loose that control it. since I had to replace some of the cluster lights also.

Now major things i need to do to this vehicle are the exhaust system and shocks/struts.

wooo almost at 100%

[igbeserk]

replaced the O2 sensor today the one you have to splice. man what a pain. but back to 1 error code. lets hope it doesn't come back.

[igbeserk]

The day after I put in the O2 sensor the error code for it came back. Finally managed to get around to buying a knock sensor won a new one supposedly denso on ebay. shipped out yesterday hoping to get it in before saturday and put it in saturday morning. I hope replacing that gets rid of the check engine light all together. then gotta do the shocks the exhaust the abs light and the airbag light issues bah lol

[igbeserk]

All right put the Knock sensor in today man that was a pain. Glad i brought my camera to take pictures so i could remember the placement. Took us about 5 hours to replace it. Started up the car still error code p0325 :-/ which is either the knock sensor or wire. so i don't know. the wire seemed ok but it's just one wire anyway since the manifold is supposed to be grounded. So i don't know what to do anymore, tired of this I replace parts and problems still occur. any help would be appreciated. i'm down to 1 code now but i'm sure the O2 sensor code will reappear in a few days like always when i erase the error codes. the new knock sensor is on the right side of the last picture. it's odd the old one is kind of bent and the new one is straight. are they made bent by toyta for those models? because the other knock sensor seemed to be bent also.