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Another significant setback...

So, yesterday I was out driving around and I got a P0500 code (vechicle speed sensor). I thought it might be caused by chafed wires as one of my turbo coolant hoses looked like it was rubbing on it a bit. I conducted a continuity test and all there wires are fine. I was really hoping for lack of continuity in one of the wires, but no such luck. So, the next thing to check is the speed sensor itself. I soaked it in Releasall; allowing it to sit for a good amount of time. The bolt felt like it was turning and snapped off. Now I can't get sensor out to test it. I am not optimistic that the sensor itself is the problem, but if I can get it off, I will test it.

The current symptoms are: a MIL with code P0500, no speedometer and the car won't shift into overdrive.

I will try to remain optimistic, but I am beginning to wonder if I should have taken this project on. Things went so well for most of the build, but issues are cropping up that are putting a serious damper on my enjoyment of this.
I'm not sure what the turbo kit has to do with this. It's something that could have happened anyway with an 11 year old car. Hopefully it's just a bad sensor or something else simple. Keep the faith. :wink:
 

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Discussion Starter #262
I'm not sure what the turbo kit has to do with this. It's something that could have happened anyway with an 11 year old car. Hopefully it's just a bad sensor or something else simple. Keep the faith. :wink:
Thanks Jim. It may not have anything to do with the kit and indeed may just be an old sensor. Or, it may be the extra torque and even possibly something to do with the way the ecu handles torque management. I'm testing the sensor soon and will post the results. As I mentioned to chemlab, if it is just a failed sensor, then that's positive, except that then I have the challenge of getting that out.
 

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Discussion Starter #263
I've got Toyota Techstream on my "car laptop" that I use to run and clear and diagnose codes on my corolla, and i can see the live feed of all the relevant temps the ECU has available on a certain page.. and A/T Fluid is one of them, among Oil temp, so i'll have to pull it out and do some runs before AND after i do my turbokit and record the data to see if my temps are different at all. hmmmm... Now i wonder what are the recommended/ideal A/T fluid temps on a stock Corolla vs when we should get a trans cooler..
Hey Cuban Legend. Can you tell me a bit more about your Techstream setup? What cable did you buy and what operating system are you running on your laptop? I'm considering picking up Techstream, but have heard about connectivty issues with some cables and operating systems. Is your cable an actual one provided by Toyota or an eBay one? Did you buy a membership from Techstream? All the details you can provide would be great.

Thanks!
 

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Discussion Starter #264 (Edited)
P0500 Troubleshooting

I got a P0500 (VSS Circuit Malfunction). The Vehicle Speed Sensor on the rear of the transmission is not working and the results are: no speedometer, dash MIL and no shift into overdrive. Shifting into all other gears is fine. I did have one point where the car would not move in gear at all. Shifting into park and back fixed that.

I did some testing today. I cut the pink wire to the connector (signal wire) and put a wire extension on it and a terminal to attach to my multimeter. The idea is to spin the wheel slowly with the ignition on (the sensor is ignition powered), and watch the multimeter as the current oscillates between 0 and 11 volts. Here is the testing procedure:



Here is the wiring diagram for the Yaris. I will have to crossreference with the xD diagrams, although I think the xD takes its speed data from the ABS system.



Test wire. When I conducted the test, the connector was reattached to the sensor.



Result. 0 volts with wheel spinning and stationary.



It seemed strange that I wouldn't see any voltage, so I decided to probe the power terminal on the connector (again, with ignition on) and still 0 volts. Here is a question, however: I did not ground the multimeter on on pin#2 of the connector, but rather on a chassis ground. Is it a must to ground the multimeter ground lead on the wire of pin#2? I can do that by making a tap into that wire of necessary.

Since I had no power at the connector (and I had previously done continuity tests - all good), I decided to move to the junction connector (A21, if I recall correctly) in the fuse box to see if it was getting power. Again, with ignition on, there was zero volts.



I have to consult my wiring diagrams and trace where this power source comes from. If it is fact from the ECU, I may have a bad ECU. If I do, I can pick up another one for around $25.00 - $30.00.

I am thinking about applying direct voltage to the VSS pin wire #1 (black wire) and repeating the VSS sensor test. However, I need to find out if the supply is 12 volts and not something like 5. I expect it's 12 volts as it is an ignition source.

Open to any suggestions/recommendations. Thanks!
 

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That's why I recommended pulling the harness off the sensor (sorry I didn't say specifically why originally) because sometimes if there's a capacitor/diode/digital-circuit or something on one of the wires involved further down the harness and it can cause weirdness in your testing. It shouldn't matter if you use a vehicle ground if things were designed in a logical way - but that's regular logic not engineer logic. Sometimes you get your answer without isolating things, but if you don't you end up having to take the time to disconnect and independently power/ground everything anyway.


That said, your diagram does show key-on should always have voltage supplied to the vss so I would be suspicious of your harness having a problem further towards the power source.

If that diagram is correct you should (with battery disconnected - and you might have to try reversing your meter probes since there's probably a diode in the harness somewhere that'll look like a fail one way and find cont the other way round) have continuity from the hot pin/wire of the sensor, back to the ecu-ig fuse which... man.. from the fuse chart i looked at online toyota just decided every part of the car should get a taste of that sweet, sweet ecu-ig circuit... windows, locks, steering, cooling fans, brake system, sensors, anti-theft.. That's a lot of possible ways to blow that fuse so check it's intact.
 

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P0500 Troubleshooting

I got a P0500 (VSS Circuit Malfunction). The Vehicle Speed Sensor on the rear of the transmission is not working and the results are: no speedometer, dash MIL and no shift into overdrive. Shifting into all other gears is fine. I did have one point where the car would not move in gear at all. Shifting into park and back fixed that.

I did some testing today. I cut the pink wire to the connector (signal wire) and put a wire extension on it and a terminal to attach to my multimeter. The idea is to spin the wheel slowly with the ignition on (the sensor is ignition powered), and watch the multimeter as the current oscillates between 0 and 11 volts. Here is the testing procedure:

..... cut for space

I have to consult my wiring diagrams and trace where this power source comes from. If it is fact from the ECU, I may have a bad ECU. If I do, I can pick up another one for around $25.00 - $30.00.

I am thinking about applying direct voltage to the VSS pin wire #1 (black wire) and repeating the VSS sensor test. However, I need to find out if the supply is 12 volts and not something like 5. I expect it's 12 volts as it is an ignition source.

Open to any suggestions/recommendations. Thanks!
wow, i have no idea how to help you, you seem WAY more competent at reading wiring diagrams and troubleshooting electrical systems than me, how did you get the first pic with info on how to check the VSS? thats super helpful , is it from a manual of sorts?

either weay, i do hope you figure out what it is and i look forward to seeing how you figure it out and i am impressed by what youve done so far in working on it. amazing
 

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Discussion Starter #267 (Edited)
That's why I recommended pulling the harness off the sensor (sorry I didn't say specifically why originally) because sometimes if there's a capacitor/diode/digital-circuit or something on one of the wires involved further down the harness and it can cause weirdness in your testing. It shouldn't matter if you use a vehicle ground if things were designed in a logical way - but that's regular logic not engineer logic. Sometimes you get your answer without isolating things, but if you don't you end up having to take the time to disconnect and independently power/ground everything anyway.


That said, your diagram does show key-on should always have voltage supplied to the vss so I would be suspicious of your harness having a problem further towards the power source.

If that diagram is correct you should (with battery disconnected - and you might have to try reversing your meter probes since there's probably a diode in the harness somewhere that'll look like a fail one way and find cont the other way round) have continuity from the hot pin/wire of the sensor, back to the ecu-ig fuse which... man.. from the fuse chart i looked at online toyota just decided every part of the car should get a taste of that sweet, sweet ecu-ig circuit... windows, locks, steering, cooling fans, brake system, sensors, anti-theft.. That's a lot of possible ways to blow that fuse so check it's intact.
Thanks a ton chemlab! I have a development that springs from a flaw in my testing. When I was looking for the power source at the fusebox, I hadn't plugged CA2 back into the fusebox. With CA2 seated back in the fusebox, I probed the pin from above and had battery voltage. I also have IGN battery voltage at the speed sensor connector, so I guess that's good news. However, when I connect my multimeter to the signal wire from the sensor, I get battery voltage - no oscillations in voltage when I spin the wheel. It just stays at battery voltage. Here's another possible factor. I checked my battery voltage today and it was just over 10 volts. I have been suspecting a weak battery for a while. I'll be picking a new one up tomorrow. I always keep it on a trickle charger. When they tested the battery today, it actually read 12.8 volts but immediately failed the amp draw test. Turns out the battery is close to 8 years old, so it certainly earned its keep. LOL. I know that low voltage can play havoc on modern electrical systems, but my VSS code popped up with the car running and charging at 14.1 volts. I will redo the test tomorrow with the engine running and with the new battery. Maybe the low battery voltage supplied to the sensor itself is adversely affecting the operation of the unit. At least tomorrow I'll have the correct voltage supply.

Anyway, with the VSS showing steady battery voltage and not oscillating, I'm leaning toward the sensor itself being the problem. I do think that bench testing the sensor is the way to go as if the nylon driven gear is broken, at least I can still spin the shaft and see if the voltge outputs are in spec. God forbid that the driving gear on the output shaft failed as that sounds like a transmission drop and case crack - something that I'm not necessarily comfortable doing.

To get the sensor off - with the broken bolt - I am going to try drilling out the broken bolt from above. I can pick up a 12" drill bit extension and it looks like I might have a straight on shot for drilling after I remove my intake and 1 heater hose. If I can drill it out, I'll tap for a new bolt. If I can't drill it out, it may be time to dig out the dremel and cut the bolt flange off the sensor. I won't really know how badly stuck the sensor shaft is in the transmission casing until I can get what's left of that bolt out of the equation. I've been offered a free VSS from another member at yarisworld if mine is indeed faulty.

A quick question about the sensor voltages when testing...With the open diff and the other wheel spinning in the opposite direction, would that affect the voltage output? I wouldn't think so.

Steady voltage with wheel turning slowly:



Broken bolt on VSS:

 

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Discussion Starter #268
wow, i have no idea how to help you, you seem WAY more competent at reading wiring diagrams and troubleshooting electrical systems than me, how did you get the first pic with info on how to check the VSS? thats super helpful , is it from a manual of sorts?

either weay, i do hope you figure out what it is and i look forward to seeing how you figure it out and i am impressed by what youve done so far in working on it. amazing
Hey. Thanks Cuban Legend. I have service manuals and wiring diagrams for the Yaris, Corolla and xD. I downloaded many, many diagrams when I was doing my engine swap and had a membership to TIS. Tell me a bit about your experiences with TechStream, which adapter you got, your laptop OS etc. I'm seriously considering investing.
 

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That's a really good question about the diff messing with the test; I've never actually tried doing this with the car in the air. The 2 times I've tested like that I didn't have 2 jacks handy so instead of lifting it I just put the car in neutral on the ground and rolled it back or forward 6ft till it hit my safety blocks on the ground.
I don't know it for a fact, but the more I think about it, you're onto something and instead of the transmission output shaft spinning, the torque you're putting into the system is just going straight through to the other wheel since that's the path of least resistance.

It's good you found a voltage. The fewer chances for it to be a harness gremlin - the better.
 

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Discussion Starter #270
P0500 VSS Testing

Please check out my video. I am getting strange behaviour from my VVS. Later, I plan to put my 2008 up on the stands, tap into the VSS signal wire and repeat the same tests and see what the voltage readings are. In the meantime, please have a look and see what you think. The weird thing is that sometimes I get a high voltage reading when I apply the brakes (wheels stop spinning) and the next time, I will get almost no voltage.

Thanks!

 

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Are your wheels turning between braking? The vss switches signal on and off really fast when you're moving. Honda's for example are something like switching at 1.12X your speed in mph so even 3 or 4 mph you're getting pulses faster than a lot of multi meters can show correctly.

I didn't see any place in the video where your brake was on but the voltage was midrange (correct me if I missed it) - it was always full or basically 0. That's the expected behavior since hall sensors put out a pretty perfect square wave if it's working; It can only send full V or 0V (multi meters can show super small voltage instead of 0 unless it's a really expensive one).

If the only 6-7v you see are with the wheels turning - that's also the expected behavior of the vss; What you're seeing is the on/off pulses and your multimeter struggling to average it out and display something that makes sense on the digital screen. Expensive meters can show you the waveform like an oscilloscope to confirm that but it sounds to me like your sensor might be working just fine.
 

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Discussion Starter #272 (Edited)
Are your wheels turning between braking? The vss switches signal on and off really fast when you're moving. Honda's for example are something like switching at 1.12X your speed in mph so even 3 or 4 mph you're getting pulses faster than a lot of multi meters can show correctly.

I didn't see any place in the video where your brake was on but the voltage was midrange (correct me if I missed it) - it was always full or basically 0. That's the expected behavior since hall sensors put out a pretty perfect square wave if it's working; It can only send full V or 0V (multi meters can show super small voltage instead of 0 unless it's a really expensive one).

If the only 6-7v you see are with the wheels turning - that's also the expected behavior of the vss; What you're seeing is the on/off pulses and your multimeter struggling to average it out and display something that makes sense on the digital screen. Expensive meters can show you the waveform like an oscilloscope to confirm that but it sounds to me like your sensor might be working just fine.
Here is the updated post I did this morning but didn't post...

Thanks chemlab!!!

Yes, the wheels were spinning at idle speed in 1st gear between braking. I guess what got me was that when the brakes are applied and wheels stopped, sometimes I got no voltage and other times I got battery voltage. I watched a few youtube vids and they all seemed to show 0 volts when the wheel wasn't spinning. Now, mind you, they were actually driving the cars back and forth slowly. My front wheels only are spinning. I don't know if that as any influence. According to the specs in the pic I posted in post#264, it explains that voltage should be from 0V - 11V. I totally get that my multimeter would show lower voltages as - like you say - it's averaging too slowly to show the peak volts. But, why would I get battery voltage sometimes when the wheels are stopped and other times no voltage? It seems to me that it should always be 0 volts with the wheels stopped.

I'm looking at better multimeters as well as oscilliscopes. I'd like to have one or the other for my shop anyway.

I'm also going to test the voltages on my 2008 Yaris and see if the voltage behaviour is the same as my '06. If so, I think we (haha, see what I did there :grin:) can conclude that my VSS is ok. Seriously, I thoroughly appreciate your help. I'm optimistic that with your input, I can get this issue solved, unless of course, it's a mechanical issue in my trans. Fingers crossed it's not! Since I am getting voltage fluctuations, I'm assuming that the driven and driving gears for the sensor are ok.

Just had a thought: I know that a wheel speed sensor's voltage is dependent upon its relative position to the wheel ring. It seems to me that this is totally different than the VSS as rotation speed only influences voltage output. Is it possible that the position of the VSS shaft has anything to do with voltage output and that when I'm sometimes getting 0 volts and sometimes getting battery voltage, that the VSS sensor shaft is just stopping in a different position? Not sure if this is clear to you or not.

Edit 2: I found this site.

https://www.troublecodes.net/pcodes/p0500/

Here is a snippet from that article:

Hall Effect Sensor: A Hall Effect Sensor has three wires: signal, reference and ground. Start by consulting the wiring diagram for your vehicle to determine which pin on the connector is which. Next, connect the red multimeter lead to the battery positive terminal and the black lead to the ground pin. You should see a reading of about 12 volts indicating a good ground. Then, check that the 5-volt reference is getting to the sensor by connecting the red multimeter lead to the reference voltage pin and the other to ground. You should see a reading of about 5 volts indicating a good reference voltage. Finally, check that there is continuity to the PCM. You can do this by touching one meter lead to the return signal pin on the sensor connector and the other to signal pin on the PCM. Set your meter to the ohms setting – you should see a value appear on the screen. If instead, your meter read OL, you have an open circuit and will need to trace the factory wiring diagram.
If the sensor and circuit test OK, there is only one item left to blame – the PCM. Before you replace the PCM however, it’s a good idea to double check your testing up to this point. PCMs rarely go bad and they are expensive to replace.


I'm assuming a hall sensor is in place as it's 3-wire. I'm going to read it again to understand the "5-volt reference". Is that the signal wire?
 

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Just had a thought: I know that a wheel speed sensor's voltage is dependent upon its relative position to the wheel ring. It seems to me that this is totally different than the VSS as rotation speed only influences voltage output. Is it possible that the position of the VSS shaft has anything to do with voltage output and that when I'm sometimes getting 0 volts and sometimes getting battery voltage, that the VSS sensor shaft is just stopping in a different position? Not sure if this is clear to you or not.
I think you're saying the same thing I did. I'm not sure if the forum here allows links but, h**ps://www.troublecodes.net/wp-content/uploads/2015/11/P0500-Permanent-Magnet-Waveform-Examples.jpg

3-wire sensors are digital hall effect sensors so they produce that on/off square wave (ignore the voltage they show that's just an example). One position on the shaft is 0v and the next position is full voltage so I think it was just luck of the draw where your sensor stopped.
2-wire sensors are that sine wave (reluctance sensors) and they can a bit*h to check with multi meters. - these will show 0V whenever you stop moving since they're creating voltage by moving a magnet past a wire coil just like how your alternator works.

I wouldn't want to pull the damn thing if it were me and it had a broken bolt on it, but you might have to just to make sure each point on a full rotation is good; I don't know that you can be 100% sure otherwise. The only time I had issues that turned out to be a vss, it was totally and obviously bad from the roll test.

I guess I just find it hard to accept the coincidence of something you didn't touch going bad when you worked on basically every other part of the car. It looks correct enough to me that I'd be 70-80% satisfied it's working.
You said that wiring harness has an extension on it to take speed from this transmission sensor instead of the abs - have you checked really carefully for loose/wobbly/corroded/dirty pins in that extension connector? And, if you plug it back into the ecu and clear the code, does it ever work even for a bit or is it just always throwing the code again immediately, maybe shaking the wiring harness a bit between a couple of attempts.

I guess it depends which wall you want to bang your head against, removing a broken bolt in an inconvenient place and unless you're super lucky repairing the threads, or painstakingly examining your harness inch by inch and every connector looking for anything that's not perfect; Either way you've got an annoying path to narrowing down the problem from the sound of things.

Just a thought, you said you can get another ecu on the cheap; It might be worth plugging another one in to test. There's always the chance you do have a wiring problem somewhere and you smoke the new ecu as well, but if the replacement is cheap enough it might be worth the "time vs money" risk gambling that the ecu was the problem and everything else is fine. At this point it's turning into a bit of a head-scratcher.
 

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Discussion Starter #274 (Edited)
I think you're saying the same thing I did. I'm not sure if the forum here allows links but, h**ps://www.troublecodes.net/wp-content/uploads/2015/11/P0500-Permanent-Magnet-Waveform-Examples.jpg

3-wire sensors are digital hall effect sensors so they produce that on/off square wave (ignore the voltage they show that's just an example). One position on the shaft is 0v and the next position is full voltage so I think it was just luck of the draw where your sensor stopped.
2-wire sensors are that sine wave (reluctance sensors) and they can a bit*h to check with multi meters. - these will show 0V whenever you stop moving since they're creating voltage by moving a magnet past a wire coil just like how your alternator works.

I wouldn't want to pull the damn thing if it were me and it had a broken bolt on it, but you might have to just to make sure each point on a full rotation is good; I don't know that you can be 100% sure otherwise. The only time I had issues that turned out to be a vss, it was totally and obviously bad from the roll test.

I guess I just find it hard to accept the coincidence of something you didn't touch going bad when you worked on basically every other part of the car. It looks correct enough to me that I'd be 70-80% satisfied it's working.
You said that wiring harness has an extension on it to take speed from this transmission sensor instead of the abs - have you checked really carefully for loose/wobbly/corroded/dirty pins in that extension connector? And, if you plug it back into the ecu and clear the code, does it ever work even for a bit or is it just always throwing the code again immediately, maybe shaking the wiring harness a bit between a couple of attempts.

I guess it depends which wall you want to bang your head against, removing a broken bolt in an inconvenient place and unless you're super lucky repairing the threads, or painstakingly examining your harness inch by inch and every connector looking for anything that's not perfect; Either way you've got an annoying path to narrowing down the problem from the sound of things.

Just a thought, you said you can get another ecu on the cheap; It might be worth plugging another one in to test. There's always the chance you do have a wiring problem somewhere and you smoke the new ecu as well, but if the replacement is cheap enough it might be worth the "time vs money" risk gambling that the ecu was the problem and everything else is fine. At this point it's turning into a bit of a head-scratcher.

Thanks chemlab! I'll have a read of your link. Thank you for that. I will reply a bit later with more details and thoughts, but I can tell you that I conducted the precise tests on my 2008 Yaris this morning and got the exact results (different voltages at different points that the wheels stopped and very similar readings with the wheels turning) that I did with my '06. There are video links below for comparison between the two cars. So, I think you are right that the VSS is probably ok.





VSS testing on my '08 Yaris:


VSS Testing on '06 Yaris:



Quick question: When you said that your VSS sensor proved obviously bad during your roll test, what was the sensor doing, if anything? Did you have weird voltages?

I had another thought around your suggestion to possibly revisit my previous wiring. I did make a harness from the plug that came from my old Yaris harness. And, I did have to move one pin in the ECU and had particular difficulty getting it reseated. Plus, I've had the main ECU plug on and off during my turbo wiring, so it's a distinct possibility that pin isn't making good contact. I will go back and check that. I will also do some more research on how to test the ECU. If I can't figure that out, I'll order another ECU and pop that in to see if it resolves the issue. In light of the fact that my '08 is showing virtually identical behaviour, would you still recommend pulling the sensor?

I bought tools just in case I need to drill the hole out. Always looking for an excuse to further stock my shop. Haha. If I can get it drilled out, there is a good amount of room to use a tap tool in there.

 

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Quick question: When you said that your VSS sensor proved obviously bad during your roll test, what was the sensor doing, if anything? Did you have weird voltages?
The two I've had to test over the years, one worked like I expected and I traced the problem with it back to a wire bundle that had broken out of it's plastic hanger on the firewall and had abraded on... I think it was on an exhaust heat shield edge but I don't really remember and I suppose it doesn't matter aside from proving I'm turning senile too young.

The one that was bad always read 0V on the signal no matter what I did. I eventually took it off and fed it straight 12v turning the shaft like your toyota maintenance procedure in the book and still got no signal-line voltage OR any amperage on the ground line when I tested that. It was burned out internally and the voltage line was just dead-ending inside the sensor.


If you're getting the same result on both cars I'd call that a working sensor and wouldn't bother messing with that bolt as long as the sensor isn't loose and letting dirt or water into your transmission housing though I'd probably put a little rtv sealant around it just to make sure it's stuck in place and sealed from the outside grime (I mean I absolutely would do it eventually, but only because my ocd would remind me every time I saw the car that there was something I should do, not because it was critically important).


You can test the ecu by sending it a square wave signal in place of the vss signal wire. You can buy variable wave generators or if you're feeling crafty you can build an adjustable one out of a 555 timer chip and a potentiometer with some extra bits and bobs for pretty cheap. h**ps://www.youtube.com/watch?v=X3bQLJe8qO0 is an example of the thing I'm talking about. I've never tried to do it myself but I remember reading years ago of someone who bought a new ecu or something and was trying to get the digital odometer to match his old one by rigging up a pulser to it and letting it sit for a few days.
OR
What's the vss worth for that transmission? Can you pull one at a scrap yard for next to nothing? Plugging it into the harness and just spinning it round by hand just like the test procedure should trick your ecu into thinking you're rolling. Might have to use a low-speed drill to turn it fast enough to show on the speedometer.
 

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Discussion Starter #276
The two I've had to test over the years, one worked like I expected and I traced the problem with it back to a wire bundle that had broken out of it's plastic hanger on the firewall and had abraded on... I think it was on an exhaust heat shield edge but I don't really remember and I suppose it doesn't matter aside from proving I'm turning senile too young.

The one that was bad always read 0V on the signal no matter what I did. I eventually took it off and fed it straight 12v turning the shaft like your toyota maintenance procedure in the book and still got no signal-line voltage OR any amperage on the ground line when I tested that. It was burned out internally and the voltage line was just dead-ending inside the sensor.


If you're getting the same result on both cars I'd call that a working sensor and wouldn't bother messing with that bolt as long as the sensor isn't loose and letting dirt or water into your transmission housing though I'd probably put a little rtv sealant around it just to make sure it's stuck in place and sealed from the outside grime (I mean I absolutely would do it eventually, but only because my ocd would remind me every time I saw the car that there was something I should do, not because it was critically important).


You can test the ecu by sending it a square wave signal in place of the vss signal wire. You can buy variable wave generators or if you're feeling crafty you can build an adjustable one out of a 555 timer chip and a potentiometer with some extra bits and bobs for pretty cheap. h**ps://www.youtube.com/watch?v=X3bQLJe8qO0 is an example of the thing I'm talking about. I've never tried to do it myself but I remember reading years ago of someone who bought a new ecu or something and was trying to get the digital odometer to match his old one by rigging up a pulser to it and letting it sit for a few days.
OR
What's the vss worth for that transmission? Can you pull one at a scrap yard for next to nothing? Plugging it into the harness and just spinning it round by hand just like the test procedure should trick your ecu into thinking you're rolling. Might have to use a low-speed drill to turn it fast enough to show on the speedometer.

Thanks, chemlab! Well, I reconnected the VSS signal wire to the connector, plugged it back in and reseated the main 2 ECU connectors. I also installed a new battery as the old one was pretty much toast. I have gone for two 15 minute drives and no P0500 code! I also replaced the battery as my old one was dying. Anyway, fingers crossed that the code doesn't return. I had hoped that I would pinpoint the exact cause, but for now it may remain a mystery.

I totally get what you say about being OCD when it comes to cars. No doubt if the code stays away, I'll still drill out and tap for another bolt.
 

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Thanks, chemlab! Well, I reconnected the VSS signal wire to the connector, plugged it back in and reseated the main 2 ECU connectors. I also installed a new battery as the old one was pretty much toast. I have gone for two 15 minute drives and no P0500 code! I also replaced the battery as my old one was dying. Anyway, fingers crossed that the code doesn't return. I had hoped that I would pinpoint the exact cause, but for now it may remain a mystery.
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Good that it's started working again; That sure sounds like it's just a pin that wasn't making good enough contact. If it pops up again at least you know the fix is probably just a matter of cleaning any corrosion off the connectors and making sure the pins are all fitting tightly. Now you get get back to the fun stuff.
 

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Discussion Starter #278
Good that it's started working again; That sure sounds like it's just a pin that wasn't making good enough contact. If it pops up again at least you know the fix is probably just a matter of cleaning any corrosion off the connectors and making sure the pins are all fitting tightly. Now you get get back to the fun stuff.
Haha, yeah, back to the fun stuff for sure. I still get a check engine light and I cringe every time as it's scanning the codes. I have a P0137 rear 02 sensor, but I don't have my cat installed yet. Fingers are crossed during the scanning that the dreaded P0500 doesn't return. Very tense. Of course, I am optimistic as it scans as my speedo is still working, lol. Thanks very much again for your help. I really appreciate it.
 

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Discussion Starter #279 (Edited)
Back to boost troubleshooting

I've been suffering boost cut at around 5 psi. Maybe saying that the max boost I get is around 5 would be more accurate. It will hit around 5 and stay there. I used my small compressor, 0 - 10 psi pressure gauge and tested my wastegate. At right around 5 psi, the flapper feels like it's getting loose. It's definitely open at around 6 - 7 psi, but I don't know if that's a fair test as there's no actual counteracting exhaust gas pressure in the turbine housing without the engine running. Then again, there probably shouldn't be much pressure in the turbine side. I need to read up more on wastegates.

Pics:







Update: Video of wastegate operation added. The wastegate flapper arm is almost unmoveable with no pressure applied. If I apply 3 - 4 psi, the flapper arm becomes loose and can be jiggled. After 5 psi, there is slight, yet visible, movement of the actuator arm. Much over 5 and I get very noticeable movement of the actuator arm. I know that there is no exhaust in the turbine side but my understanding is that the pressure on the turbine side would be minimal as it's flow through.

 

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Discussion Starter #280
CAT installed and new downstream 02 sensor

Pics to follow.

I got the high flow CAT installed today. It has a bung for the 02 sensor. I installed a new 02 sensor I had on my shelf. My old sensor itself probably works but the wiring was in pretty bad shape - twisted. I once again fell victim to the no voltage, not up to temperature, downstream sensor mistake. I had initially installed my double defouler and couldn't get the sensor hot enough to registed any voltage. So, I removed those and ran the car, revving it a bit, then the B1S2 gauge sprung to life. So, hopefully this should kill the P0137/138 codes I was getting. If I get the catalyst efficiency code (P0420?), I'll reinstall one defouler.

While the car was on the hoist, we noticed that my downpipe was a bit loose. I had retorqued them after the install, but not after I'd been driving the car. Probably heat cycling caused the nuts to loosen. I'll give them, the manifold nuts and turbo to manifold nuts all another good torquing. I has really hoped that it might have been the cause of my only reaching ~ 6 psi (Yes, I am now able to reach 6 psi). The car drives well overall and is very peppy!
 
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