94 Es300 Transmission Shifting Problems

[nigel]

To all club members,

I finally solved a puzzling problem with my 4-speed auto transmission on my Wife's 94 Lexus ES300 (95,000 miles). This problem started in January, 2003. The automatic transmission occasionally hesitated (sticks) in first gear when taking off slowly from a stop. It could take up to ten seconds for the transmission to finally shift into second gear after removing your foot from the gas pedal. This condition progressively got worse until it reoccurred at least once in every three take offs. It didn't seem to matter if engine was cold or fully warmed up. There were no obvious problems with the transmission other than the shifting as stated above. The driver had to always remember not to do any quick (jack rabbit) takeoffs from a dead stop, such as accelerating to merge into the flow of traffic. Doing so could cause the tachometer to red line before you realized what was happening. Also if you pulled out quickly into traffic and your trans fails to shift, your loss of acceleration could cause an accident. I searched the Internet, and called several trans shops, and Lexus dealers. I had it checked at a trans shop and one Lexus dealer. No one could diagnose the route cause. For 11 months there had been no codes to help diagnose.

Finally after 11 months (and a threatened divorce if the problem was not corrected) I got some clues. The engine check light and the OD (Odometer) off lights came on the dash. Also the speedometer started to go to "0" when the car was moving. I took it back to the Lexus dealer and finally there was a code that indicated the speed sensor. Even after reading the code the dealer didn't think that was the problem and suggested the code and all the new symptoms were unrelated. They recommended exchanging the transmission for an extra $3500. I said no thanks, and had to pay another $190 for their advice before I could get the car released. I took it to a transmission shop the next day. They replaced the speed sensor (located on the outside of the transmission). This corrected the hesitation in shifting from 1st to 2nd gear, all dash lights, and the speedometer problems. The faulty speed sensor caused all these problems. This same transmission has been used on several Lexus model years (at least a million cars). I am amazed that all sources seemed baffled by the trans shifting problem. I don't think this is a one in a million occurrence. I hope my frustrating and expensive experience can help other club members.

Nigel

[Lextech2k3]

ok as a technician for lexus i can say two things about your experience...

1.) that WAS a one in a million shot cause that has never been scene at the dealer i work at ..and toyota/lexus has kind of a saying for things like that " if it's wrong on 4 cars in one month it will be wrong on every other one." or something like that...point is that i have NEVER even heard of this happening...but if anyone has heard of this happening...or has had it happen please tell me so i can identify this problem and bring it to the attention of my supiors as something to spread the word about...

2.) you should go back to your dealer and rip that service manager a new one!....that's a bunch of bullhonkey that they charged you 190 bucks when they were wrong...just make sure you bring a reciept from the other place to prove you had the work done...you could probably get a free service out of them as they tend to cave really quick to agressive people.

hey thanks for the insight i hope that i can save someone some trouble with it.

[SKperformance]

I have the same problem on my 94 ES also where it will redline and bounce off the tach until i let off the gas ,then it shifts.

I would have suspected the throttle cable adjustment on mine .But i have other problems of clutch debris clogging the valve body which needs to be removed to be cleaned before it will work properly again.As i have to clean the filter ever so often other wise the tranny gets no fluid as the filter is plugged and it just gets stuck.

My speedo always works normally though.

[Latoilette]

speed sensor failure. i've heard of it a while back. (not for a lexus though)

i thought those things are indestructable

[RPrindl]

I had to replace a transmission mounted speed sensor on my 85 Dodge Daytona Turbo-Z 5-speed many years ago. Took the old one apart and found a small brush, just like a DC electric motor. The brush had worn and wasn't making contact. A little Allen-head setscrew could have been adjusted to fix it, but I replaced the sensor instead. I asked the guy in the parts department if they go bad, he said "put it this way, we have 7 in stock".

It sounds like poor programming by Lexus that the OBD2 system wouldn't pick this up as a problem sooner. Some Electronics Engineers in Japan should commit hari-kari over such sloppy work!

[nigel]

Just wanted to clarify some things in my previous comments. I had metioned that my OD (Odmeter) off light had came on. I meant my OD (overdrive) off light. This light flashed slowly on and off and appeared on the dash display at the same minute that the engine check light came on. Also, the transmission shop owner told me that the computer and electronic controls on some cars are often complex and have back up systems so if the primary source of a speed signal for example is inoperative, the speedometer or other controlled items may be able to pick up a signal from a secondary source. This could make it dificult to diagnosis some intermittent problems without an obvious code to find the root cause. As far as the transmission is concerned, I had polled several dealers about transmission problems. I got the impression that Lexus dealers in general don't want to spend the money to train their technicians on auto transmission diagnosis and repair because it is such a specialty area. The general implied consensus I got from most was that if they don't know, they lean toward exchanging the transmission. As in my case, if I had agreeed to the exchange and the actual faulty component was included in the package, the problem would have been solved for $3500 - $4000 and I would not have known that I got ripped off. The dealer may not have known either and this would be continued as a standard Dealer remedy. I had asked the Dealers I called if they had got any feed back from their rebuilders after they tear down these transmissions. They all said no. That's a scarry and expensive thought for the owner.

Have a nice day, Nigel

[Ninja61871]

How much is that sensor and where is it located. or how does it look like. I have a 93 es300 and it is doing the same thing. How can you tell if the sensor is bad? is there a way to test it with a volt meter???

[lenaturaliste]

my '94 ES300 is having the same symptoms!

there needs to be a recall on this at some point <_<

[SKperformance]

a recall. the car is 11 years old.

If you had a chrysler you wouldn;t be suprised.

the price of a lexus is nothgin of a land rover but they brake as soon as they leave the dealer new and you get boned for the repair since they hardly honour there warranties.

[nigel]

Hey guys,

Here is some more info requested on the Speed Sensor I had replaced last month.

Vehicle Speed Sensor

DATA TROUBLE CODE: P0500

CIRCUIT DESCRIPTION

.... Please see picture 1 in the attached doc

PURPOSE

The Vehicle Speed Sensor (VSS) reports road speed to the Engine Control Module (ECM) . This information is used for the speedometer, transmission shifting, to synchronize emission systems and to adjust for various engine demands.

OPERATION

The sensor is a reed switch that is controlled by a rotating magnet. As the magnet passes under the sensor the contacts close momentarily, resulting in a ground signal. The frequency of these ground signals sent to the ECM is relevant to vehicle speed. The Vehicle Speed Sensor outputs a 4-pulse signal for every revolution of the rotor shaft, which is rotated by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the Engine Control Module. The Engine Control Module determines the vehicle speed based on the frequency of these pulse signals.

DIAGNOSTIC TROUBLE CODE P0500

No vehicle speed sensor signal to Engine Control Module (when vehicle is being driven).

TROUBLE AREA

· Open or short in vehicle speed sensor circuit.

· Vehicle Speed Sensor

· Combination meter.

· Engine Control Module.

LOCATING AND REMOVING OF THE VEHICLE SPEED SENSOR

The Vehicle Speed Sensor is attached to the outside/top of the trans axle case with one 10 mm hex head bolt. To locate use a flash light and look down between the firewall and the throttle valve assembly. The Sensor is approx 9" from the firewall and about 12" below the throttle assembly. Unplug the electrical connector, remove the hex bolt, and lift out the sensor.

Note: there are numerous sensors on this vehicle. Two of the Lexus dealer parts dept people I called, before I knew the OEM part #, could not determine the correct sensor. They finally guessed and gave me a price on the wrong part? The correct one will have a small gear on the lower end of the sensor.

INSPECTION AND TESTING OF VEHICLE SPEED SENSOR

.... Please see picture 2 in the attached doc

1. Connect the positive (+) lead from the battery to terminal 1 and negative (-) lead to terminal 2.

2. Connect the positive (+) lead from a Digital Volt Ohmmeter to terminal 3 and the negative (-) lead to terminal 2.

3. Rotate the shaft.

4. Check that there is a voltage change from approximately 0.0 volts to 11.0 volts or more between terminals 2 and 3. The voltage should change 4 times per revolution of the Vehicle Speed Sensor shaft.

5. If operation is not as specified replace the Vehicle Speed Sensor.

Electrical testing of other circuit components such as the Combination meter and ECM is also possible. However, if you need to go beyond the sensor test I have already included you’ll probably need more technical assistance. Most of us (Do It Yourself Mechanics) like myself, who have little or no Auto computer or electronic control training and no special diagnostic equipment at home are at the mercy of the dealers and other specialty auto shops. When we need a code or more than a standard multi (volt) meter we are out of our area of expertise. At that point we either pay to have someone service our car or learn to live with the irritation of having an intermittent or permanent problem and put up with the nuisance as long as the car is still drivable.

If the car is driven by our wife, paying someone may be the only option. :D

The OEM Part No. for the Vehicle speed sensor (aka speedometer speed sensor) is 8318112040. This part from the dealer will set you back about $210.00. You may be able to buy an off brand sensor at a discount auto parts store or from a salvage yard for less.

My old man was an electronics design engineer. He was usually an optimist, but he used to say that the more electronic bells and whistles that were put on cars, the more that would eventually fail. He drove standard cars his entire life and was much happier than his friends that did not.

I hope this info helps ………Nigel

vehicle_speed_sensor_inspection___testing.doc

[SKperformance]

thank you very much from all members for your extremly thorough follow up

it may save a few members behinds if not trannies

including mine which i am about to check, when it gets warmer to do so.

[eidanyosoy]

Thanks to this old thread I was able tto fix the same problem on my 1994 es300 today, Part from oreilly's Auto Parts was 175.99 by BDM I believe.

[eidanyosoy]

Thanks to this old thread I was able tto fix the same problem on my 1994 es300 today, Part from oreilly's Auto Parts was 175.99 by BDM I believe.

Cancel That, worked for 15 miles with overdrive, and now the same exact issue.

[nayshun]

I have an 94 ES300, and when I put it in drive or reverse or any other it will not drive. I reset the ECM plenty of times, and it worked a bit here and there but then it just stops. The car wants to move but then it doesn't and it hesitates. So I am thinking it is the Speed sensor after reading your guy's post. I am trying to find one now and see if this is the cause. But my problem is, that I do not know which sensor toactually replace to even hit the problem on target. Im going for the one on the side first which is the cheapest. Its a black sensor that is called Transmission Speed Sensor. Advanced Auto Parts has it as part number SN7138 71.99. If you guys have any suggestions please call me on my cell.

443-876-8685 - Ali

[wbwii]

Interesting that this old thread pops up today. I just ordered a "vehicle speed sensor" today from Napa online for $100. I have the same symptoms that Nigel had. I checked the Lexus service manuals and counted the number of blinks that the OD (overdrive) light gives as a code. My code is 42 stating that the primary speed sensor is bad. I will keep everyone posted of if this works or not. One additional observation is that when the speedometer indicates "0 mph" the odometer is not working. So, I don't know exactly how many miles are on my ES300, which shows 150,000 miles.

Bill

[ngleshaw]

I am also experiencing a similar problem with getting out of first gear. I would be cruising at 5k RPMs in first gear at ~25 mph. My only difference is that when my car starts to warm up, the symptoms disappear and the car would shift out of first and into second normally. I just fixed a check engine light that gave a bad O2 sensor message. We'll see if replacing just the O2 sensor will keep that check engine light away.

I was wondering if there is anyone else also having this transmission shifting problem, where it would go away once the engine is warmed up. My mechanic used his electronic diagnostic machine to get the code for my check engine light, and did not see any errors for the transmission.... Come to think of it, maybe it might see the error if the engine wasn't warmed up?

Anyway, it would be nice if I could get this problem fixed.

[wbwii]

Well, I replaced the vehicle speed sensor and so far so good. The speedometer needle and odometer work. We will see what happens over the next couple weeks.

[ngleshaw]

Interesting that this old thread pops up today. I just ordered a "vehicle speed sensor" today from Napa online for $100. I have the same symptoms that Nigel had. I checked the Lexus service manuals and counted the number of blinks that the OD (overdrive) light gives as a code. My code is 42 stating that the primary speed sensor is bad. I will keep everyone posted of if this works or not. One additional observation is that when the speedometer indicates "0 mph" the odometer is not working. So, I don't know exactly how many miles are on my ES300, which shows 150,000 miles.

Bill

Bill,

You mentioned that you checked the service manual and counted the blinks that the OD light gives. How is this done? And which service manual do you refer to to get the code? I'd like to see if I get a similar code.

I just took in my car for a check engine light, but it was just 2 oxygen sensors gone bad.

How's the shifting going for you so far?

Chris

[Ern]

Mine only worked for 5 miles! I had it changed at the dealer and they said that the o/d light would come on but it would not stop the car from working properly. Wrong answer. It is worse now and they said that it could only be the computer since they changed the Speed Control Sensor. Any suggestions?

[jamaicayute]

Does anyone have a a copy of this document? Thanks. Trying to change my speed sensor but do not know where its located.

[jyoung84]

Sounds like the speed sensor does not fix all of everyone's problems. Here is what happened with mine. Had the same shift problems. Would not shift out of first when cold. For a while it worked after the car warmed up. Then it even started having problems when warm. I had bought the car used so I changed the tranny fluid and filter. No help. Started getting check engine and OD off lights. Usually said something like Too Lean Bank 1. I did however have one OBD2 code that read out a Knock Sensor. I would not have dreamed that a knock sensor could cause shift problems with the tranny. Especially when the car seemed to be running smoothly (no pinging.) Nothing else seemed to work for me so I changed out both knock sensors. Not a quick job since you have to pull of the intake manifold to get at them. I have been driving the car for at least six months since changing them and it has never missed a shift. Knock sensors cost about $130 each (x2) from O'Reillys plus intake manifold gaskets etc. but it was worth it. Also, I recommend that you replace the knock sensor wiring harness (dealer only item) while you have it torn appart. There is also a cooling system hose undereath the intake manifold that you should get from the dealer to replace while your at it.

My guess is that if a knock sensor is sending a false signal to the computer that the engine is pinging then it will not allow the transmission to shift until the pinging stops. Not sure but my works like a champ now. Oh by the way mine is a 1999 ES300.

[Fahim Fahhad]

Interesting that this old thread pops up today. I just ordered a "vehicle speed sensor" today from Napa online for $100. I have the same symptoms that Nigel had. I checked the Lexus service manuals and counted the number of blinks that the OD (overdrive) light gives as a code. My code is 42 stating that the primary speed sensor is bad. I will keep everyone posted of if this works or not. One additional observation is that when the speedometer indicates "0 mph" the odometer is not working. So, I don't know exactly how many miles are on my ES300, which shows 150,000 miles.

Bill

i have the same prob, last 6 month... now itz clutch sensor

[lex6000]

so after fixing few other things on my car, i realize i need a speed sensor too. the problem is which one of these will get the job done.

from advance auto parts>

bwd speed sensor $166

bwd speed sensor 2 $77

ones from napa>

napa speed sensor $249

napa speed sensor 2 $129

napa speed sensor 3 $116

oreillys>

oreillys speed sensor, 2nd one on list for transmission

thanks

[nigel]

Does anyone have a a copy of this document? Thanks. Trying to change my speed sensor but do not know where its located.

I started my original thread about my vehicle speed sensor for my 94 ES300 back in Jan 13, 2004. Apparently the attached pictures with detailed inspection and test info that I attached to that post have been deleted after 73 downloads and five years from the original post date? Sorry, I have not been actively reviewing this post. I don’t get automatic e-mail prompts when someone has a question on a post that I have started or replied to. So, I only know about questions if I happen to be checking my old threads on the forum, which is rare. I tried to reattach the files, but the forum won't allow me to attach my diagrams anymore from my personal computer files, and I don't have these on a website to provide a link for you. If the documents are archived on the forum somewhere, I could not find it. If you still need location and testing diagrams with more info on inspection and testing of the speed sensor, please reply to this post and let me know. You will have to include your personal e-mail address so I can send it directly to you.

LOCATING AND REMOVING OF THE VEHICLE SPEED SENSOR

The Vehicle Speed Sensor is attached to the outside/top of the trans axle case with one 10 mm hex head bolt. To locate use a flash light and look down between the firewall and the throttle valve assembly. The Sensor is approx 9” from the firewall and about 12” below the throttle assembly. Unplug the electrical connector, remove the hex bolt, and lift out the sensor. This is very easy.

Note: there are numerous sensors on this vehicle. Two of the Lexus dealer parts dept people I called, before I knew the OEM part #, could not determine the correct sensor. They finally guessed and gave me a price on the wrong part?

The correct one will have a small gear on the lower end of the sensor.

PURPOSE

The Vehicle Speed Sensor (VSS) reports road speed to the Engine Control Module (ECM) . This information is used for the speedometer, transmission shifting, to synchronize emission systems and to adjust for various engine demands.

OPERATION

The sensor is a reed switch that is controlled by a rotating magnet. As the magnet passes under the sensor the contacts close momentarily, resulting in a ground signal. The frequency of these ground signals sent to the ECM is relevant to vehicle speed. The Vehicle Speed Sensor outputs a 4-pulse signal for every revolution of the rotor shaft, which is rotated by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the Engine Control Module. The Engine Control Module determines the vehicle speed based on the frequency of these pulse signals.

The DIAGNOSTIC TROUBLE CODE is P0500 (on the 94 ES300), which indicates there is no vehicle speed sensor signal getting to the Engine Control Module (when vehicle is being driven).

If replacing the speed sensor does not correct the problem, you may have a related issue that involves the following:

· Open or short in vehicle speed sensor circuit.

· Combination meter.

· Engine Control Module.

INSPECTION AND TESTING OF VEHICLE SPEED SENSOR

1. Connect the positive (+) lead from the battery to terminal 1 and negative (-) lead to terminal 2.

2. Connect the positive (+) lead from a Digital Volt Ohmmeter to terminal 3 and the negative (-) lead to terminal 2.

3. Rotate the shaft.

4. Check that there is a voltage change from approximately 0.0 volts to 11.0 volts or more between terminals 2 and 3. The voltage should change 4 times per revolution of the Vehicle Speed Sensor shaft.

5. If operation is not as specified replace the Vehicle Speed Sensor.

Electrical testing of other circuit components such as the Combination meter and ECM is also possible. However, if you need to go beyond the sensor test I have already included you’ll probably need more technical assistance. Most of us (Do It Yourself Mechanics) like myself, who have limited Auto computer or electronic control training and no special diagnostic equipment at home are at the mercy of the dealers and other specialty auto shops. When we need a code or more than a standard multi (volt) meter we are out of our area of expertise. At that point we either pay to have someone service our car or learn to live with the irritation of having an intermittent or permanent problem and put up with the nuisance as long as the car is still drivable.

If our wife drives the car, paying someone may be the only option.

The OEM Part Number for the Vehicle speed sensor (aka speedometer speed sensor) for my 94 ES300 is #8318112040. This part from the dealer will set you back about $210.00. You may be able to buy an off brand sensor at a discount auto parts store or from a salvage yard for less.

Sorry, This original attached file info is no longer active on the forum.

vehicle_speed_sensor_inspection___testing.doc ( 100K ) Number of downloads: 73

I hope the above info helps ………Nigel

[tak222]

Does anyone have a a copy of this document? Thanks. Trying to change my speed sensor but do not know where its located.

I started my original thread about my vehicle speed sensor for my 94 ES300 back in Jan 13, 2004. Apparently the attached pictures with detailed inspection and test info that I attached to that post have been deleted after 73 downloads and five years from the original post date? Sorry, I have not been actively reviewing this post. I don’t get automatic e-mail prompts when someone has a question on a post that I have started or replied to. So, I only know about questions if I happen to be checking my old threads on the forum, which is rare. I tried to reattach the files, but the forum won't allow me to attach my diagrams anymore from my personal computer files, and I don't have these on a website to provide a link for you. If the documents are archived on the forum somewhere, I could not find it. If you still need location and testing diagrams with more info on inspection and testing of the speed sensor, please reply to this post and let me know. You will have to include your personal e-mail address so I can send it directly to you.

Please can you send me a copy of the diagram to doetack [at] yahoo [dot] com. Thank you