RottiesOnBoard

New to the boards but I got some great info searching posts as a guest for the past month. Now a member and have a more specific problem. No speedometer, cruise, odometer. ECU throws a Code 42 and O/D light flashes after traveling over 10 miles.

After searching the boards here, I removed TVSS and tested with multimeter-no reading. Opened the back of the part and noticed the round pick up magnet under the triangular cover was cracked.

I tried the TVSS rebuild as seen at https://www.yotatech.com/forums/f116/speed-sensor-rebuilt-write-up-250730/ (thanks to Go Blue! It was a great write up but didn’t work in my case probably because the magnet was cracked.)

Replaced TVSS Part #8318135051 using a vendor mentioned on one of the VSS threads, reset ECU, drove 2 miles, still no speedometer, cruise, or odometer. ECU threw another Code 42 within 2 miles. Disconnected 3-prong plug on TVSS and probed the harness using a multimeter with engine running and got intermittent “ping” signal (I’m assuming the reading was the ECU pinging the TVSS for information).

Removed new TVSS and got a signal on the multimeter while spinning the gear by hand.

So now I hit a road block. What’s the logical next step? Yank the dash and test connections on speedometer portion of instrument cluster?

Also, I’m looking at buying a 4Runner to part out depending on the year. It’s a V6 4x4 auto sitting in front of a junk yard/tow recovery place down the street. What model year range parts are compatible with a 93? Will parts from a 90 ~ 95 work or should I look at just 92~94 model year 4Runners to part out? The truck I’m looking at was a multiple roll over and will be a total as far as insurance in concerned. Parts for my 93 are hard to come by in this area and the junkyards won’t part out individual pieces like a TVSS. They want you to buy the whole tranny for just that one part. Therefore my thought to just buy the entire heap (depending on model year) and strip down what’s still good on it, then sell what’s left for scrap.

Thoughts, ideas, opinions greatly appreciated!

AsIGoAlong

My sensor went out too. Speedometer, Odometer went out and after 100 miles driving long distance, my check engine light and O/D light came on. Checked codes and both concluded the problem was VSS.

So, I too tried https://www.yotatech.com/forums/f116...ite-up-250730/ to no avail. Figured I'd buy one from CarQuest, installed it, and my Speedometer/Odomter still don't work.

I haven't reset ECU, but didn't think that would matter. I also haven't checked the harness prongs to see if it's a wiring/relay issue.

I was wondering if anyone had other steps I should try, since I already dropped $230 on a new part. RottiesOnBoard, how have you solved it?

scope103

There's a procedure to test the speed sensor here: http://www.ncttora.com/fsm/1990-1995...e/combinat.pdf You'll need some "micro" alligator jumpers, but if you can use a multimeter you can do this test.

That will tell you if the sensor is okay. Then plug it in and turn it by hand -- any indication? (This allows you to consider that the transmission is not turning the gear).

Finally, before I replaced the combo meter, I'd use an ohmmeter to check each wire from the panel to the plug.

Me, I used a signal generator to "simulate" a sensor; my speedometer read the "speed" so I knew the problem was in the sensor. But not many people have a signal generator ...

AsIGoAlong

Thanks Scope103. I attempted the VSS test you stated in the link from the FSM. I checked all my connections several times on the multimeter. I would test the mm by touching the connections to the battery directly and would get a 11-12 V range. (So I know the multimeter works at the proper range)

I would then immediately properly, using alligator clips, touch the VSS. Without spinning the speed sensor shaft I would get a 0.02 with the new sensor and a 0.05-0.08 with the old sensor. While spinning the sensor shaft, the multimeter would not change at all.

So now I don't know if I'm doing it all correctly. Shouldn't the mm change if I spin it? According to the FSM, a range of 0-11V is within range. I guess I'm at the very bottom end of that range, but it doesn't change while spinning.

I'm wondering if I wasted money on a new VSS b/c the problem is somewhere else or did I buy a defective VSS. (NOTE: the VSS from auto parts stores don't include the speed sensor shaft that has the gear at one end to connect inside to the transmission.)

Thoughts for a next test?

scope103

The signal on pin 3 is "conditioned digital," meaning it goes from nominal 0v all the way to 12v 4 times/revolution. If you did the test correctly, both your sensors failed.

What the manual says is that it has to change FROM 0v TO 11v or more (and back again). So you are nowhere near the minimum 11v.

Remember that the sensor is powered (it's a hall effect sensor that drives a little integrated circuit; the IC needs power). So you need 12v hooked up in addition to the multimeter, just like it shows in the manual. And those pins are very tiny; I sure had no easy time make sure I was correctly connected. A reading of 0.02-0.08 on most less-expensive digital multimeters is what you'll get when the leads are connected to nothing. (They may be picking up a little energy from your fluorescents, for instance.)

But if you've done the test correctly, you've got a bad VSS, and it will never drive the speedometer.

AsIGoAlong

You are right about me using a cheep multimeter.

I have now concluded I've been working on the wrong VSS. I should be working on the Number 1, not Number 2 VSS. The #1 is in the combo meter at the dash. The #2 is next to the drivetrain.

I say I've been working on the wrong one b/c several weeks ago when I received a O/D signal code of 42. That corresponds to Sensor #1 (See image from FSM)

Thanks for you help, without saying.

scope103

Do you have a cable speedometer? I thought you had an electronic. The rebuild link you cited is for the electronic speedometer. This is an electronic VSS1 :


VSS1 is in the back of the transfer case. VSS2 is the speed sensor in the transmission. VSS2 is for the transmission. But since you have a 2-speed transfer case, you can't get the road speed from the transmission. You have to have a sensor downstream of the transfer case.

The VSS1 "in the dash" is only for cable speedometers.

AsIGoAlong

Well now I'm confused. I do have, and have been working on this whole time, the VSS corresponding to the image you posted above, Scope103. I just thought realizing my code 42 in the FSN corresponds to #1 which is where the combo meter is at the dash. (NOTE: I don't have any O/D or check engine lights coming on)

I do have, according to your image, the VSS1 which is the electronic one.

So, looking at my first image, for code 42 it tells me to check VSS #1 which leads me to the page for the second image I included.

Are you telling me this is the VSS which is under the vehicle at the drivetrain or the one at the combo meter behind the dash?

It seems like there are different definitions of what VSS #1 vs. #2 is.

In image 3 it shows the VSS #2 which looks like your VSS #1. Again, this is why I think I've been working on the wrong VSS and should be working on the combo meter one.

scope103

VSS1 drives the speedometer. So, if you have 4wd, you'll have a 2-speed transfer case. Where do you want to get the speedometer signal? After the transfer case. So VSS1 is the one in the back of the transfer case. (The test procedure is your second picture; it's a 3 terminal device which requires power to operate.)

VSS2 controls the shifting of the automatic transmission. Where do you want to get that speed signal? Before the transfer case (the transmission is shifting based on output rpm; it doesn't care how fast you're actually covering ground). Your 3d pic shows VSS2 (surprised that the FSM is correct?). Note that it is a 2-terminal device (basically a switch).

Here's a better drawing (for an A340H Transmission):


AsIGoAlong PM'd me with links to the two sensors from Autozone (this was news to me; these sensors are usually a dealer item. But Autozone's price is about the same as the dealer this time). She also asked if VSS2 could be removed without disassembling the transmission. The answer is: I don't know. But based on the drawing above (and the photos on Autozone) it looks like it is held in with triangular bracket, held on by a single bolt. Intended to be removed with the transmission in place.

DO run the test procedure first. Your code could be due to things other than a bad sensor (wiring?), and you don't want to be someone "throwing parts" at a problem.

AsIGoAlong

I finally got back around to working on this over the weekend.

I replaced the VSS 2 (passenger side), which is the one with the shaft that goes directly into the tranny. I was able to replace the VSS 1 (driver side), but had a pickle doing so. The wiring harness goes up over the tranny and the only way to unhook it was pull out the auto shifter and access it from the top.

I also found a replacement computer from a junkyard and switched it out. All this to no avail.

I've done this work to b/c the trouble codes have given different troubleshooting solutions.

Scope103, I now agree with you that it's wiring. Since I've tried all these other solution to no avail, the only troubleshooting element on the trouble codes for both the CHeck Engine and the O/D is wiring.

Here are images of the Codes. I continue to receive Code 42 for both.
First is for CHeck Engine and second is for O/D:

Of course I still don't understand why it states "Combination Meter"

So, My question is what's the best way to check wiring and where to even start? The Combo meter works, every other instrument works except the speedometer and odometer.

Not sure how or where to check wiring. Suggestions?

GACK2_92_4X4

Does any one know where I can get just the gear for the vss1 (passengerside)?
There are two missing teeth in which I have no idea on how that happened. Or would that even effect the speedometer?

RottiesOnBoard

Sorry I haven't followed up on my thread. Priorities with the truck have changed into a motor replacement. High oil pressure when cold that drops to about 2PSI once warmed up. I would think this indicates the main bearings are worn out. So in the mean time, the speedometer has been replaced with a GPS unit. At least no speeding tickets and I'll know how fast I'm going when I blow the engine!

GACK2_92_4x4 - I got my passenger side VSS from 1aauto dot com. It came with the gear and sensor all in one and ran about $80.00 plus shipping. Hope that helps.

GACK2_92_4X4

Ok so I tried to take it apart and clean it out like I read on another thread, but i snapped two of the screws trying to take the top off... so thank you for the information man and i sorry to hear about your motor. good luck with the new one.
Could you possibly send me the page you bought it from, cause im having a hard time finding it from 1aauto.com ....mine is a 92 but i think it should fit but i should check that out too thanks.

cheappc

So did you ever get the solution to this? thanks..

RSR

Scope -- My google and/or manual searching abilities on the A340H seem to be failing me. Is the torque value on the VSS1 retaining bolt 8 ft-lbs like the A340F transfer case (only value I could find was for the separate tcase)?

Thank you!