Speedometer crazy and transmission shifting crazy and slipping - sometimes
330,000 miles. When cruising on the highway, the trans will sometimes
downshift crazy and the speedometer sometimes goes to zero. Some days I
have not problems at all. Usually happens when its warm on the highway but
after it starts, it'll happen an slow speeds. After a day of rest, its typically OK
- for a while.
Replaced BOTH speed sensors on the transmission
Replaced the instrument cluster.
Getting ready to solder the leads to the speed sensors to eliminate the plugs
as a source.
Anybody have any other ideas?
at 330K miles and the original transmission, I'd say your overdue for a rebuild. Consider it a good thing, you got your money worth out of it.
If this Tranny is Computer Controlled....I would road test this vehicle with a Scan Tool in place checking inputs and outputs. Have you noticed any warning lights ON or Flashing? What does the Tranny Fluid look/smell like?
I have had it scanned several times but not wile driving. The diagnostics at AutoZone always indicate: "Vehicle Speed Sensor Circuit Malfunction". That is why I replaced both VSS sensors. I replaced the transmission filter an fluid after the problem started. It was way, way, way over- due. It was dark. I cleaned the ground contacts on the ECM, including the contacts on the board itself. I could not quite figure out what fuse/link supplies power to the VSS's - (let me know if you do know). I pushed down hard on all the fuses/links in the engine box and dash box. Surprisingly, most of the links (not fuses) were NOT 100% seated and went down just a hair. Hmmmm.... After 14 years and 330,000 miles perhaps they start to loosen up a bit.. Drove the car > 100 miles today with no issues - so far. We shall see.
Ok...good History. This may be a wiring problem between the VSS's and the Computer. Now we need a DVOM(Digital Volt Ohm Meter) and a wiring diagram. The Code ID(letter and number) would ID which sensor/circuit is faulty....the DVOM will tell us if a signal is reaching the Computer The wiring diagram will tell us which wires/colors to check at the back of the computer to test. So...having said all that....WHO is going to run these tests. The signal being sent by a good VSS is usually AC Voltage...thus...we need to know a little about Auto Electricity to complete the diagnosis. Not knowing your background in this area...you might consider a good repair facility. Keep us up to date on this interesting issue.
I began the process of attempting to find where the circuit goes for the 2 VSS units. It is hard to find good information. What I did do was to push down on all the fuses/circuit breakers in the engine and dash fuse panels. I was surprised to find that most of the breakers/links where NOT FULLY SEATED. I guess after 14 years the vibration backs them out - just a hair. Not much. But I wonder.... anyway, its been about a week and hundreds of miles without a significant problem. Could it be???
With the technology used on these cars......I would not be surprised if you may have "fully seated" and solved the problem....however...if/when the problem resurfaces...I would suggest an immediate stop to where ever you have Computer Codes Scanned. Write down the ID of any Codes to include the Alpa/numeric ID, Get back to us for further analysis.
The code is "Vehicle Speed Sensor Circuit Malfunction" - seems obvious - but - The problem is recurred but is very sporadic. I might go for days without a problem then it'll crop up for about 5 minutes - then go away. I checked the connectors to both VSS units again and they are firm. I wish I knew where those wires went so that I could check them all along their path....
The VSS Sensor...is it a 2 wire sensor or a 3 wire sensor. What colors are the wires?
It was 2 wires - I would have to remove the air box again to get the colors. What do you think?
Time to regroup and clarify. When I go online and search for a VSS for a 2002 Camry....I see a 3 Wire sensor for Automatic Trans. I see a 2 wire Sensor for a Standard trans. So...What Tranny is in this vehicle....and....are both of these VSS located in the Transmission. Can you take a picture of both Old sensors and post?
UPDATE....This is what I have found......you will need a voltmeter to check for an AC voltage at the ECM. D connector. (L)...means BLUE. Front wheels must be turning.
Hope this helps
Another interesting note. Seems there is a Toyota Service Bulletin that addresses this issue. TBS-0072-10. Code P0500. Does that code ring any bells?
Yes - I'm pretty sure that is the code. I don't find anything when I google that TSB number - can you send a link to it?
Thanks for that diagram! Where did you find that? Based on it, the two sensors go directly to the ECM - surprise to me! each are 2 wire in the diagram. If I get desperate - I can run new wires to the 2 VSS units :)
I will look more closely at those wires when I next get a chance - thanks!
Here is another thought I just had. 2wire speed senors are usually magnetic reluctor types. They have a coil of wire rapped around a magnet. If the end of the sensor picks up a lot of dirt and Metal Particles....it effects the operation of the sensor. If you still have those old sensors....it might help if I could see a picture of said sensors.
Oooops...a small typo error above. That Service Bulletin # is TSB-0072-10.
I replaced both sensors last summer - they were clean. The local Toyota dealer wants $125/hr to "look" at the car when all I want is and updated ECM. Do you know a mail-order solution for that?
I assume an "updated ECM" ,...really means Re-flashing the ECM that is in the vehicle. That process is usually performed by a Toyota Dealership. It would be a lot cheaper to invest in a DVOM from Wal-Mart and make an attempt to check the wiring from the sensor to the computer...and...the signal coming from the sensors to the computer.
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